 I think we are already live, so we can start with this webinar. So hello everybody, I am Roberto Lineros from IFIC, University of Valencia and SESIC in Spain, and I'm going to be the host of this webinar, of this series of the Latin American webinars of physics. So today we are going to have a very interesting talk because it's about leptogenesis that is closely related with the matter-antimatter asymmetry. We know that the universe is a form of mostly matter. So, but before with the talk, I want to tell you that if you want to make questions during the webinar to Diego, that is the speaker today, you can do it via the... Here is the information, Google Q&A and in Twitter with the hashtag L-A-W-O-P. And of course, if you want to contact us, you can simply write it in Twitter or in Gmail via email. So, let's talk about the speaker. Today's speaker is Diego Ristisabal from the Université de Liege in Belgium where he is an assistant professor in that institution. He obtained a PhD in physics in the University of Valencia and after that he has done two postdocs, one in Trascati in Italy and another in Liege also. So the title of his talk today is leptogenesis beyond the type one seesaw and I guess we can pass to Diego. Let me just unmute you. Oh, let's see. I cannot unmute. You have to unmute yourself. There is in the upper part the bar. Like that, right? Okay. So, Diego, how are you? Yeah, I'm good. Thank you. So first of all, thank you for the invitation now. Not only to you, but all the members of the crew which are running this great idea of the Latin American webinars. Yeah, so... So if you want, you can... All the people is listening to you now. You have the control of the webinar. Okay, so I will start with my presentation now. So as we already said, I'm going to speak about leptogenesis beyond type one seesaw. So I hope I can make my point clear. So basically, so let me see if I'm able to put this in the way it should be. Okay, here it goes. Okay. Are you listening, Roberto? Yes, I'm listening to you and I can see your slides. Yeah, but the point is that I haven't been probably going to full screen mode. Oh, no, now it goes. No, now I can see it, perfect. Okay. Okay, so as Roberto said, I'm going to speak about leptogenesis beyond type one seesaw. So this talk is intended to be rather than something where I discuss particular results, a review talk. So the idea will be just to present, to give a motivation to this scenarios, which I call beyond type one seesaw. Try to explain what is the main idea behind going beyond this standard leptogenesis picture. So as soon as I review the basics about leptogenesis, which I think anyway is something useful, particularly for those which are not involved in this kind of physics, I'll move on to more specific things. In particular, I will discuss probably, I won't be able to discuss all the three papers I want to deal with, but at least I aim at discussing this paper, which I wrote past year in collaboration from people in Brussels. This other one, which I wrote a few years ago in collaboration with people from the Josef Stefanistitut in Slovenia. And hopefully, as I said, if I have sufficient time then I will discuss as well some results I got past year in collaboration with Avelino and people from Valencia, Professor Valle and Mariam Tortula as well. So let me go to my motivation. Of course, when you discuss this subject, from my point of view, the first thing you have to discuss is the current status of Neutrino data. So partially, one of the motivations for this kind of scenario is where you try to address the bionysymmetry puzzle of the universe by a mechanism named leptogenesis. It's related with the origin of Neutrino masses. So this basically, this slide summarizes what we know about Neutrinos nowadays. So people know and we know, what we know is that this oscillation parameters, Neutrino oscillation parameters, the atmospheric scale and the solar scale, they are derived from global fits to Neutrino oscillation data. So this Neutrino oscillation data covers water, Sharenko reactor, long baseline in radiochemical experiments. So the plots I have here which I took from this reference, summarize what we know, what we nowadays know about the Neutrinos oscillation parameters. So the plots on top show the Delta Chi-square distribution for the solar, atmospheric and the reactor mixing angle, which three years ago it was proved experimentally that it doesn't have a vanishing value. So current fits to oscillation data actually favor a reactor mixing angle with a value of about 90 degrees. Now the plots here in this part of the slide correspond to the solar mass square, the atmospheric mass square, so mass square differences for the solar sector and the atmospheric sector and this other one as well shows something that people have been discussing for a while and is the fact that it might be that already data is hinting to a non vanishing Delta CP phase. So if you look to the best point value for the Delta CP phase and you realize that if this hint turns out to be true the Delta CP phase should have a value which amounts to 3 pi over 2. I don't have nothing else to add that respect. I just want to point out that there are other ways, experimental ways to which one can gain information about neutrinum axis. These other ways are summarized here so these are constraints coming from neutrinum level beta decay from which the best limits on this quantity are placed by Gerda Exo and Campbell and Sen and tell us that this quantity should have a value which amounts to 0.2 basically. Then there are other services from which one can strain neutrinum axis. Kinematic experiments which rely on kinematic end point measurements of the beta spectrum are determined by these two experiments, Mines and Trotsk and tell us that neutrinus should have a mass below 2.2 eb. So of course when you compare the values you get from neutrinum oscillation experiments and you get as well from neutrinum as a little bit to decay then you realize that kinematic experiments are not that competitive but certainly provide a complementary information of the full neutrinum picture. And then cosmology as well provides limits on the sum of the three active neutrinus. So occurring values provided by Planck and also by baryonacoustic oscillation experiments tell us that this quantity should be about below 4.23 eb. Now the overall picture when one looks to this experimental data is that certainly neutrinus are massive and moreover we know that actually this year Nobel Prize went into that direction. Now this is certainly a proof that we have to go beyond standard mode. We need new degrees of freedom and basically in my opinion the whole goal of determining the origin of neutrinum masses consist on pinning down the scale at which neutrinus are generated. Certainly what we know is that we have to go beyond the standard mode given this experimental information. Now there's another intriguing data and probably it's not even relying on data. It's actually something of the everyday life so we know that there is more matter than anti-matter. This quantity, the baryonacymmetry of the universe has been measured precisely via cosmological experiments, astrophysical and cosmological experiments. So the basic idea is that in the cosmological standard mode, light element abundances, so I'm speaking about the uterium, helium-3, helium-4 so on and so forth these abundances, they are a function of the baryonacymmetry of the universe so as soon as you have information about these abundances you can fit your cosmological model and determine the value for which you get consistently the values observed as a function of the baryonacymmetry of the universe. Now it turns out that not only those measurements but also measurements of the C and B provide information about the baryonacymmetry of the universe. Now it turns out that the C and B spectrum, the shape of that spectrum depends upon the value of the baryonacymmetry so as soon as you have information about that shape you can go you can fit your model and from that fit you can derive as well a value for the baryonacymmetry of the universe and actually when you compare those values so those values are shown here in this plot the vertical orange strip is the range you get from measurements of light element abundances while the vertical blue strip is the one you get from measurements of C and B so when you look to this overlapping because actually there's an overlapping here suddenly you can conclude that this is a great achievement of the standard cosmological picture because measurements of light element abundances or when you speak about light element abundances you are speaking about BBN which is an epoch in the early universe that completely differs from the epoch of radiation decoupling which is in turn the epoch at which you can speak about C and B physics so we are speaking about completely different physics and on top of that we are speaking about completely different eras during the evolution of the early universe the fact that these two numbers mesh so precisely is in my opinion a great achievement of the cosmological standard mold now of course given this information the goal will be sticking to the standard mold investigating whether you can generate such an asymmetry well people did that and they realized that you cannot do that so since this experimental information is pretty solid is as well probably at the same footing that neutrino oscillation data it is in my opinion a definitive proof that one has to go beyond the standard mold now of course it will be nice the goal will be to find a common framework where you can address such puzzles so in principle they are unrelated but it turns out that when you stick to leptogenesis these two puzzles turn out to be related and here is how it works so in a mold independent fashion you can generate neutrino masses by the inclusion in the standard mold like Grandin of dimension 5 effective operator the so-called Weinberg operator now this effective description is pretty powerful and is pretty powerful because after electro-exymmetry breaking you end up generating a matrix that has this form this matrix already suffices to explain neutrino oscillation data but of course you want to get more you want to pin down the region of the degrees of freedom which are inside this black box this is basically the goal of investigating the region of neutrino masses however there is a feature no matter the mold you rely on related with this operator this operator is left to number break so you have left to number violation if you can assure as soon as you put this operator at the like Grandin level that you have new sources of CP violation that you might probably even get from these couplings and you can guarantee the partial from thermal equilibrium then in that case you will necessarily end up generating an asymmetry in the a leptinosymmetry in the early universe alone that leptinosymmetry will be capable of generating a bearing a symmetry but it turns out that in the standard mode there are non-pretivative processes related with this failure on reactions such that when you generate a leptinosymmetry this is failureons transfer part of that asymmetry into a bearing asymmetry so the picture the general picture let's say the model independent quotation marks picture you get is that you enforce your like Grandin to involve matter and neutrino masses and then when you couple that with a failure on processes you necessarily end up generating a non-vanishing bearing asymmetry so in this kind of scenarios leptogenesis scenarios you necessarily end up relating two in principle unrelated puzzles the region of the bearing asymmetry and the region of neutrino masses and it's from that point of view that this scenarios are in my opinion and probably for many other people a pd now how does this work in type one season so basically conventional wisdom is that neutrinos acquire masses by the type one season which means that if the Weinberg operator is generated by the exchange of heavy right handed neutrinos you can write a set of new interactions so you have Dukawa reactions Dukawa couplings let's say they will be reactions anyway we like to call this for the time being Dukawa reactions so you have these Dukawa reactions and then you have major and a mass terms for the new objects here now these major and a mass terms they break lepton number necessarily and the Dukawa couplings you can prove involve physical cp phases so you have cp violation encoded in the Dukawa couplings and you have lepton number violation encoded in turn in the major and a mass terms now if you summarize what you learn from this like Grandien then you end up with the following picture you have cp violation given by these couplings you have lepton number violation given by these new terms and then if you can guarantee that you can departure from thermal equilibrium you will certainly end up generating a net non vanishing lepton massimetry now the departure from thermal equilibrium is provided by the expansion of the universe so this is a dynamic which is occurring in the early universe being subject to fast expansion expansion provides the conditions that you need to satisfy so to generate a net lepton massimetry now this picture has been throughout analyzed in all possible ways and certainly when you stick to the picture where you have a hierarchical right handed Neutrino spectrum you can argue that what you have is the canonical picture for standard leptogenesis basically the type one CISO provides the framework for standard leptogenesis now of course given what I already pointed out it will be worth wondering whether one can go beyond that picture there's no reason why one cannot but of course everybody knows that the devil is in the details so one has to go and check for other possibilities other possibilities are well motivated so in principle one can argue that other realizations of the winder operator do exist and are as motivated as the type one CISO so if I stick to type 3 and type 2 CISO let me explain why I mean by that so in type 3 CISO rather than exchanging electric singlets you exchange electric triplets, fermions as well so the winder operator you get through the exchange of this heavy fermion triplets in type 2 CISO instead your re-completion is such that you generate the winder operator via the exchange of heavy scalar triplets now of course I wonder whether this kind of realizations are not motivated well my point of view is that they are phenomenologically and theoretically motivated now phenomenologically I mean the following so the number of UV completions you can think about when you write the winder operator is pretty large so this has been recently proved however when you stick to these two realizations type 3 and type 2 they are as simple as the type 1 CISO and you can argue that they are as simple as the type 1 CISO because when you count the number of parameters that type 3 CISO involves they amount to the same quantity that the type 1 CISO has when you go to the type 2 CISO you realize that even in that case you are able to generate neutrino masses and the number of parameters you have are smaller even than the type 1 CISO so from that point of view they are well motivated now theoretically one knows that the type 1 CISO certainly something that fits pretty well with the gut paradigm so you invoke SO10 then you place your fermions in the 5 dimensional representation and you know that out of that you always get right hand and no treat you get electric singlets now it will be or it is worth wondering whether this is the case for type 3 and type 2 CISO and it turns out that is like that if you stick to minimal SU5 so you know that fermions you place them in the 5 dimensional representation and also in the 10 dimensional representation the HIC sector and the minimal realization consists of a 5 dimensional representation but if you want to let's say guarantee the tau unification you probably have to add a 45 dimensional representation now gut breaking can be achieved in several ways but the minimal way is certainly by the joint representation and then of course in that setup without lepton number violation you cannot generate no treat no masses and you want to do that so imagine you want to construct an SU5 got them all capable of generating no treat no masses so what do you get in that case well there are several ways in which you can proceed if you add a 24 fermion then necessarily you will have right hand and no treat and also electric triplets so basically in SU5 enlarge with a 24 dimensional representation fermionic of course you always end up with a sort of interplay between type 1 and type 3 if rather than relying on a 24 fermionic dimensional representation you stick to a 15 scalar representation then in that case your SU5 will generate no treat no masses via type 2 now the bottom line of this discussion is that type 2 and type 3 are as motivated probably or have sufficient motivations to wonder whether one can actually achieve as it turns out to be in the type 1 C so an explanation for no treat no masses and an explanation for the region of the baryon asymmetry of the universe so now let me go to let to then this is in the type 3 C so I think I have to speed up because I was told that time is about 30 minutes I basically running out of time type 3 C so okay what do I mean by that so these are the kind of interactions you can think about in type 3 C so you have gage processes, you have yukawa processes and of course you have madron amass terms which break leptom number now I won't go into the details of how you can generate no treat no masses and do scenarios but anyway I just want to mention that the mechanism through which you can generate no treat no masses in type 3 C so resembles what you do in type 1 C so now the yukawa as I said in the type 1 case in this case turns out to be like that as well they involve new cp-violate interfaces these new cp-violate interfaces induce triplet cp-violate in the case the amount of cp-violation you can encode in this quantity epsilon which is just a cps- symmetry and it turns out that when you impose no treat no data and you enforce your spectrum to be hierarchical you can show that the cps- symmetry is bounded such that you have successful leptogenesis only when your triplets have masses above 10 to the 10 dB now you can of course turn this argument around and saying that if you have a quasi-degenerate spectrum the way function p's that determines the cps- symmetry will be resonantly enhanced and so in that case it has been argued that probably you can have successful leptogenesis for order T e v triplets now what are the processes you have to be in mind and to hit that so remember that you have to guarantee lepton number violation you have to guarantee cp-violation encoded in this case in the couplings and then on top of that you have to guarantee that your states the portion for the thermal equilibrium now if you want to address that question you have to account for different processes taking place in the hit bath so this slide is rather technical but I just want to point out that the relevant processes for a reliable calculation of the v-sella symmetry are just the decay inverse decay of course which provides the necessary washouts to generate sufficiently large v-sella symmetry and of course the corresponding one loop corrections to these processes one has to include as well something that at first sight seems like higher order processes so I'm speaking about processes of this type which correspond to a channel exchange of triplets the point is that in the absence of loose states you cannot end up with kinetic equations which are thermally well behaved so you have to add them anyway now this process you can forget about because this process in particular these two are suppressed by extra Yukawa couplings however the processes I have here you cannot neglect so the guys I have here are guys that have non-trivial electro-wick charges they couple to gage bosons in a non-trivial way as shown here in this pi-mon diagrams then you have to take them into account because these gage processes are fast and they tend to thermalize the triplet distribution now if you want to account for this thermalization then you probably have to write kinetic equations the kinetic equations I'm speaking about have this form so you have a kinetic equation that accounts for the evolution of the triplet density and of course you write a Boltzmann equation a kinetic equation for the evolution of the b-l charges and the different flavors depending on whether you are not in the flavor regime now when you do that you look to this equation to realize that there's a competition basically between Yukawa related processes and gage processes so this competition is somehow shown here in this plot so here this plot I'm showing a couple of numerical examples for the behavior of the gage reaction densities so here with gage reaction densities I mean number of reactions per unit volume per unit time now the blue line here corresponds to a gage reaction density for a tripled mass of 10 to the 8 dB the red instead corresponds to the gage reaction one obtains for a tripled mass of 10 to the 11 dB these other two curves correspond to this reaction densities those driven by Yukawa couplings now I can realize looking at this plot I'm plotting here this reaction densities by the way normalized to this quantity as a function of set where set is just the ratio between the tripled mass and the temperature one is like a dimension less temperature parameter so when you look to this expression you realize that basically depending on the relative size of the tripled mass and this parameter until though which encodes the information about the Yukawa coupling depending on the relative size of these two parameters you end up either with a scenario where in the case of the coupled of the coupled gage reactions which means gage reactions that go below this line you have or not the coupled inverse decay as well so this curves here they refer to inverse decays and for example if I go to the tripled case where the mass is fixed to 10 to the 11 dB then I realize that when this gage reaction decouples the inverse decay is still active the inverted decay decouples later on but if I go to the case where the triplet has a mass of 10 to the 8 dB then I realize that when gage reactions become fast the inverse decay is the coupled as well so these behavior this competition between gage reactions and the case controlled by or inverse decays controlled by Yukawa couplings really plays a role in this scenarios now before going into the actual results I would like to mention the behavior of the lepton asymmetry in the unflavored case now it turns out that you can analytically integrate the equations you end up with a result of this type now here you have three fundamental quantities so you have the CPS symmetry in flavored I you have this factor which is the thermal distribution for the triplets and then you have as well something which is the efficiency factor which you have to determine by integration of kinetic equations now this means that if you want to know what is the amount of b-cell you can generate it is sufficient once you fix the CPS symmetry to calculate for the efficiency so this plot here shows the efficiency as a function of the parameter m tilde for different values of the triplet mass which I took to be 10 to the 10 10 to the 11 and 10 to the 12 gb the regions one can identify here there is a region of the small m tilde where one can realize that there is a strong dependence on the triplet mass so the efficiency strongly depends upon the value of the triplet mass and there is another region of large m tilde where you see that there is basically no dependence as soon as you start moving from a certain threshold on m tilde so as soon as you start moving from that threshold from m tilde the efficiency becomes independent upon the triplet mass no matter the value you take for the triplet mass you always get the same value now this means that in those regions of parameter space basically the gauge reactions are subdominant compare with those reactions driven by jukawa couples now this observations allows to split another space of this model in two pieces one piece which I like to call gauge region and another piece which I like to call jukawa region they both obey to the polynomial definition now the jukawa the gauge region sorry is a region where when gauge decoupling takes place in the case of the couple as well and the jukawa region is the other way around in the sense that when gauge reactions are the couple in the first case still act now naively even without doing any calculation you expect that if you put flavor effects into the game those effects should have an impact basically in the jukawa region because gauge reactions are flavor blind so no matter the flavor configuration you take you always will end up basically with the same amount so no matter whether you have flavor effects or not you will always basically end up with the same amount of b-sella symmetry now here I have a sketch for what do we mean by leptome flavor effects I will go through this slide rapidly given that I'm running out of time now but basically the point is the following so there are three lines of reactions you can think about in the standard model which are dependent upon leptome flavor so these are the jukawa couplings of course now if the reactions related with the jukawa couplings are not fast which means their rate processes their rate is smaller than the expansion rate then of course the leptome double is the rate and the spaces of time are just superposition of the different flavors with the composition determined by these factors that tell you which amount of tau, mu and electron flavor you have in that particular leptome delt now if you have a standard model related reaction which is leptome flavor sensitive and it turns out to be fast fast here means faster with the expansion of the universe then you might end up breaking the coherence of that quantum state it turns out that people investigated that like about 10 years ago and basically the point is that you can divide the temperature regimes in different windows depending on whether certain reactions are not fast, fast compared with expansion rate of the universe now these are the windows you can think about, I won't go through them, I just want to point out that for the results I'm going to present in the next slide I will stick to this window the window where both the bottom Yukawa coupling and the tau Yukawa coupling are in thermal equilibrium now when you include flavor effects of course you have to specify a given point and parameter space and for that aim the flavor compensation of your leptome doublets you can specify using flavor projectors so for this particular two examples I have here I have fixed my flavor projectors according to these values there's no motivation behind that rather than just highlighting the main physical features of the behavior of the b-minus cell asymmetry the presence of flavor effects and then the absence of flavor effects so the results are divided in the two regions I already pointed out gauge region and Yukawa region and well in this plot where I'm basically showing the efficiency magnified by a factor 10 to the 4 as a function of set for these two parameters fixed according to 10 to the 12 for the triplet mass and 2 times 10 to the minus 4 for the effective treatment mass if you want it to call it that way so basically the parameter that is determined by the Yukawa couplings so in this plot I'm displaying two results one for the flavor regime which corresponds to the red dotted line and one for the flavor regime which corresponds to the blue curve now as expected in the gauge region you don't have basically any enhancement due to flavor effects and as I already pointed out the reason is that in that region gauge reactions they do play a role and since this gauge reactions they do play a role and they are flavor blind there's no reason why you should expect in that particular region of parameters space to have striking effects due to the inclusion of left of flavor if you move instead to the Yukawa region you realize that the picture completely changes so for the same point for this point but changing the m tilde parameter from 10 to the minus 4 to 10 to the minus 2 remember that moving from one region to another for a fixed triplet mass determined just by the change of m tilde you can realize that in that case when you move deep inside the Yukawa region the enhancement you get on the resulting efficiency or if you switch on the b-minus sign which is striking so you start having enhancements of two orders of magnitude so certainly once you realize that you can split the parameter the parameter space region of this kind of models in two pieces you know that whenever you want to have flavor effects into the game you want to have sizable flavor effects you necessarily have to move to the Yukawa region well I have here other result which basically shows the the same picture that I already ended up in the previous slide so I think I rather skip this one and I would like to ask Roberto whether I can keep going or you believe it is worth stopping here I think that it would be nice if you can continue a little bit more okay so I think I can be done in like in 8 minutes or so and I apologize for such a long time okay so let me move on to the leptogenesis in type 2 scenarios now the idea here is rather simple doesn't differ too much from the from what you get in type 3 cesium in certain aspects however there is a major difference regarding Neutrino mass generation it is well known that you can well account for Neutrino masses in the presence of a single triplet so a single triplet suffices to generate Neutrino masses in agreement with experimental measurements that's it now if you want in addition to that to address the barren symmetry puzzle then you have to go beyond that minimal picture going beyond that minimal picture is not unique you can do that in several ways so you can for example argue that rather than having a single triplet you have more than one you have whatever number you wish or you can think as well of having a sort of hybrid scenario where you don't only have triplets but you have the Neutrino this will be actually the kind of scenarios you will end up with if you stick to SU5 with K with fermionic representations line in the 24 dimensional representation fermionic of course now let me just say why this idea doesn't work if you just have a single triplet now if I have just a single triplet I can only think about a one loop correction to the corresponding decay something of this sort now if you look to this plot to this sort to this final diagram then you realize that this diagram is one particle reducible you can cut this diagram here so in principle it looks like a correction to a decay but it's not a correction to a decay it's just the self energy of the triplet so of course in that case you don't have any contribution to the any one loop contribution to the triplet decay into leptons now if you move into the picture where you all offer additional degrees of freedom you add for example extra triplets then you can think about two loop two possible one loop corrections to the decay so you can have something of this sort or you can have something of this type now this two pieces they differ and they differ in a non-negligible way in the following sense so when you look to the diagram then you have something which is lepton number violating here so in addition to the yukawa couplings and to the gauge processes which are determined by kinetic terms you have a trilinear scalar coupling this trilinear scalar coupling breaks lepton number so when you look to this kind of processes you know that necessarily they will involve lepton number violation this one instead involves only yukawa couplings and these yukawa couplings are lepton number conserving so these kind of corrections are lepton number conserving while this one is lepton number violating as I already said you can as well if you like if you better like type 1c so you probably can stick to pictures where you have interplay between type 1 and type 2 and then in that case you will have corrections to this decay determined by this kind of processes now let me focus some pure type 2 contributions meaning only scalar triplets now in that case as I said you have 2 contributions to the cp violating phase you have one which is flavor of lepton number violating and you have another which is not sensible to the fact that you have or not lepton number violation now this piece not carrying about lepton number violation enables purely flavor leptogenesis and this is something that that these people and myself and collaborators pointed out past year what do I mean by purely favor leptogenesis well in this kind of scenarios it turns out that the cps symmetry is lepton number conserving meaning that the different pieces that determine the cps symmetry they break they break lepton flavor but they don't break lepton number so when you sum over lepton flavors your total cps symmetry vanishes something that has been noted long long ago probably 20 years ago or so then of course you have to wonder if you have a cp lepton conserving quantity how come you can end up with a b-cell asymmetry well you can write in the two flavor regime you can write your cps symmetry in this way if you write in this way and you recall that the b-cell asymmetry can be written as the cp violating asymmetry times the efficiency then you will have two contributions one which will be the efficiency of the tau flavor and another one related with the efficiency in the a flavor now the only way through which you can get an unvanishing b-cell asymmetry is if your efficiencies don't match and if you want to guarantee that you necessarily have to guarantee in turn that your washouts are lepton number violating okay so this is the point in Taiwan C so you find as well this kind of behavior so in Taiwan C so you have two contributions to the cp violating phase the lepton number violating one goes as the ratio of m in 1 to 2 and 3 while the lepton conserving one goes as that ratio to the second power which means that if you stick to the conventional standard leptogenesis picture where you have hierarchical neutrinos this piece is always subdominant it might be relevant and it turns out to be relevant actually in scenarios where you have a slightly broken lepton number scenarios with slightly broken lepton number necessarily involve quasi-degenerate spectra and if you have quasi-degenerate spectra there's no reason why this term should be more relevant than this other now in type 2 the same behavior but the parameter dependence is completely different so the lepton number violating piece depends upon if you wish on the branching ratio of the trip to going to final state leptons basically depends upon the kawa couplings the lepton number conserving piece instead depends upon the branching ratio of trip that going to scalars or if you wish to the trilinear scalars kawa couplings this means that whenever you go to scenarios where the branching ratio of the trip that going to hexes is much more smaller that the branching ratio of the trip that going to leptons you always end up with dominance of this piece and therefore you can think about constructing in that way pure flavored leptogenesis schemes now of course if you want to do that again you have to do the exercise with thinking what are the relevant asymmetries you have in the thermal bath this is a bit tricky in this case because the triplet is not a self conjugate state as it turns out to be for example in the type 1 case so you have to account for a triplet asymmetry which is sourced by the b minus l asymmetry now you have as well this is a key point you have as well an asymmetry in hexes because this guy the triplet not only decays to leptons but also to hex double hex now the point or the question is how can you treat the asymmetry you generate in hex degrees of freedom now there are 3 possible reactions you can consider you can consider reactions which are much more much more slow than the expansion of the universe so this basically those reactions are so slow that at the time where you calculate the asymmetry you are generating they basically haven't happened so you can't forget about them then you have reactions which are fast compared with the expansion rate these reactions you can resume through chemical equilibrium conditions and then you have the reaction that you have to treat via kinetic equations now in this atop the b minus l asymmetry you track using Boltzmann equations while the hex asymmetry being shared by all the other degrees of freedom of the standard model which are fast should be resumed by chemical equilibrium conditions now bearing that in mind you have to consider all the possible processes that I won't discuss just want to point out that you have any way to consider gage reactions because these guys have nontrivial charges under SU2 cross U1 and then if you do that you end up with a very nice picture for purely flavored leptogen which works in this way this is a sketch of how it works when we tackle that problem past year what we did was properly integrating the kinetic equations and treating all the possible effects including as I said chemical equilibration but here with this sketch it's pretty simple to understand how the picture for PFL within type 2C so it works so as I said you need to wash out to be lepto number conserving but when you sorry, violating to this expression at first sight it seems like this quantity is lepto number conserving because it's driven by this branching ratio which are controlled by Yukawa couplings which don't break lepto number now the point is the following in the initial stage just in the initial stage you generate through the source term the same amount of B-cell asymmetry along the tau and the A direction that asymmetry that you generate sources the triplet asymmetry but it sources the triplet asymmetry weighted by a factor that has a flavor structure and so it weights the different B-cell asymmetries in different ways and necessarily generates a non-vanishing triplet asymmetry now once you have a non-vanishing triplet asymmetry in the bath you of course will have more triplets than anti-triplets or vice versa if in the heat bath you have more triplets than anti-triplets well of course you will end up with more leptons than anti-leptons so the lepto number violation you need in washouts basically provided via that mechanism so this triplet asymmetry here you have provides somehow the lepto number sources you need so to guarantee that your washouts are lepto number violation the sketch is like as I draw here so at the beginning you have same amounts of B-cell asymmetries in the tau and the A direction then in the stage where you still don't have any lepto number violation in the heat bath these two amounts you have the triplet which due to this weighting flavor dependent factor end up sourcing the washouts and at the end you end up with a mismatch between the B-cell asymmetry in tau flavor and in A flavor and of course with an asymmetry in the hicks as well so this is a mechanism which relies entirely on a triplet asymmetric plasma that enables having in the presence of delta E equal to zero decays a non-vanishing B-cell asymmetry this is just a result just to have fun of the behavior of the parameter space of this setup which shows the maximum B-cell asymmetry you can get in this kind of PFL scenarios these PFL scenarios based on a triplet density which is asymmetric in the heat bath as a function of this R parameter which is defined in this way and which encodes the information about the possible flavor structures you can conceive the value you want to generate amounts to 10 to the minus 11 so that you can for different values of this R parameter you can always generate sufficiently large B-cell asymmetry even if you impose an neutrino data as we did so the green points are for the normal spectrum the red points are for the inverted spectrum so even in that case you see that you can always generate sufficiently large B-cell asymmetry so you end up with a very nice picture you can generate the B-cell asymmetry you explain neutrino masses and you do that through leptin conserving triplet decays which at first sight seems, quotation marks counterintuitive now I want to close just by mentioning other non-standard variations given that I won't have time to discuss the last part of my talk what I can think about interplays between type 1 and type 3 CISOs these are things that I did some time ago with these collaborators of mine so if you conceive scenarios where you have a certain small hierarchy between the right-hand neutrinos and the electric triplets then they both will participate in the generation of the B-mine cell asymmetry and of course in those cases depending on the regions of parameter space you deal with you can end up with sizable enhancements of the B-mine cell asymmetry as well then you can conceive as well the possibility of generating dynamically the right-hand neutrinomasses in which case if you rely on global leptin number breaking then you will end up with new degrees of freedom including a madron the presence of these new scalars can potentially affect the way in which leptogenesis takes place even in the type 1 CISO this is something we investigated past year and then of course you can stick to other pictures sorry to other realizations of the Weimber Operator one loop to loop realizations this was done about 10 years ago by Tomohan B and some of his collaborators it turns out the bottom line of this analysis is that if within your realization you have states that have nontrivial SU2 cross U1 quantum numbers then these guys will couple to gauge bosons and then this coupling to gauge bosons will produce thermalizations down to low temperatures which in turning implies lower bounds on the masses of these new states then the new masses of these new state of bounds can be in principle used provided you can produce these guys of LEC to rule out some of these scenarios for leptogenesis well that's it these are my conclusions I let you read them I think it's sufficient for now actually I took me almost actually an hour I hope some of you are still tuned so that's it ok thank you very much Diego it was a very nice talk I mean the topic is very interesting so now we can let me just adjust some stuff here in the hangout ok so now we can start with the question so before to start with those I just remember to the public the ones that are following the streaming that you can make question via the Google plus Q&A system and in Twitter with the hashtag L-A-W-O-P so let's start first with the question from the public that we are here in the hangout maybe someone want to start sorry do I start sharing my screen you have to stop to ok let's see your face also if you get scared with the questions or not I might get scared yeah so let's start with I have a couple of questions one before the people start this question if the L-A-C will be able to reach some of these questions some of these models what is the perspective in the future this is something that has been discussed recently actually so somebody you have just close to your room Martin Hears he wrote a paper past year where they pointed out that the discovery of left a number of violating interactions at the L-A-C will basically not rule out completely but will introduce certain tension in scenarios for standard leptogenesis in general for mechanisms where you rely on the production of the B-minus L-A-C through left a number of violating interactions at the high scale in that case the main point is that no matter how large the asymmetry you generate at high scales the washouts imply by those reactions that you are observing at L-A-C will wipe out whatever you generated now of course there is a loophole in that case because it might be that you generate the asymmetry in certain flavor okay so it might be that at the L-A-C you observe certain flavor structure now if you observe certain flavor structure it might be that you can still store certain amount of lepton asymmetry in that given flavor but certainly this puts some constraints on this leptogenesis scenarios which rely on high scale mechanisms so this is one of the things that would be nice to observe at L-A-C I mean per se of course it would be great to discover left a number of violating interactions at the L-A-C or whatever we can discover but certainly the observation of left a number of violating interactions at the L-A-C will probably probably speaking rule out this idea of generating the lepton asymmetry via a violation of lepton number at high scales up to the loop calls I pointed out and then you also asked about other ways well these other ways rely on a different on a different way of thinking so as I said when you have states that have SU2 cross U1 non-trivial charges this guy is coupled to gauge bosons if they are very light they are thermal lies basically down below the temperature at which its failure is decoupled if you are generating on a symmetry you need the aid of its failure to reconvert that quantity into a baron asymmetry so you have to guarantee that your states don't decouple before its failure in decoupling you will realize a bound on the masses of those states typically at least for type 2 and type 3 the number you get is about 2.3 2.5 TV okay now I don't know whether the lec has capability for producing such states but if the lec turns out to produce a state which has a mass below 2.5 TV let's say a scalar triplet or a fermion triplet then in that case let's say you find a state which has a mass of 1 TV in that case you can guarantee that that state alone cannot be entirely responsible for the baron asymmetry of the universe so the observation of a light state at lec will basically up to loop holes will rule out the possibility of generating the asymmetry by either type 2 or type 3 so in that sense means that one possibility is just to have this flavor that the genesis that you were presenting in my opinion my understanding of this problem is that you cannot avoid having flavor effects provided your leptin flavor dependent reactions are faster than the expansion rate this is determined by the temperature at which leptogenesis takes place so as soon as you go below that temperature basically as soon as you go below 10 to the 13 GEV you know that your setup or your analysis should rely on flavor degrees of freedom so in my opinion my understanding is not up to you you have to include them because this is a physical process which implies basically quantum decoherence of a state that before the reaction was fast was completely quantum coherent thank you maybe someone else has a question otherwise we continue with the questions that are already in the Q&A system so okay now we have another question from Andres Felipe Rivera Romero so he's asking to you what about the three-body decays like alternative to generate the leptin asymmetry in the fukujita genjida classic model it works is it not necessary in your case I mean he's asking about three-body decays yes he cannot turn off the microphone probably it will be better because he's just following the streaming so he only can write questions maybe he can compliment the question now probably so he's talking about three-body decays in which scenario in the model of fukujita genjida so he's thinking about rather than the three-body decays yeah maybe well I don't see how these three-body decays can compete with a two-body decay and actually I mean if you have if I properly understand his question so the decay one has is a heavy guy a heavy guy a guy that has mass of the gut scale they came to leptin and hexes so I cannot think about the three-body process in that case yeah maybe he can't explain what kind of three-body process he's speaking about probably I can give an answer yes maybe we can ask Felipe Felipe to compliment a little bit his question maybe we can pass to another one I have a question here from Jose Valle I guess it's related with the first one with the first question of all he was attending my seminar yeah yeah he was looking he's around I guess he's in his office okay tell Professor Valde that it's a honor for me that he's attending my seminar virtually attending so if the leptin number violation in the LAC then you you roll out the leptogenesis picture right Martin's paper he's quoting so basically this is what I said up to Leupold you roll out the leptogenesis picture in the sense that if you observe the states the leptin number violating the states we have masses that say at one TV you cannot say nothing below one TV so if you can think about a mechanism that generates the asymmetry in the size that has to be generated below one TV then you cannot say nothing because at that point washouts don't play any role so if you observe a state a leptin number violating the state at one TV then of course you can exclude all possible mechanisms from that point above as I said up to Leupold and the Leupold basically is storing the symmetry along different flavors so basically you have to make a definitive claim in my opinion you have to determine the flavor structure of your new leptin number violating physics for example if your leptin flavor structure is such that is democratic in all flavors then you are done you know that all these mechanisms are ruled out but if it turns out that this new physics is such that it couples more to leptins sorry to towels while basically it doesn't couple to electrons there's no reason why you wash out in electrons should wash out completely the symmetry you generated at the God scale if you wish I understand the point it's very interesting in fact to go beyond the standard scenario all the flavors are the same and everything I think making a definitive claim I mean the claim is sufficiently strong but a definitive claim like saying you rule out leptogenesis occurring above certain critical energy scale the scale to which you produce data lec requires determine as well the full structure the full flavor structure of your new physics okay so I guess this question is answered so maybe okay let's go with another question this is related more with okay if it is still possible to have leptogenesis when you generate the neutrinos masses at one loop you have a kind of conserved charge for between neutrinos to acquire masses at level and only who is asking that me okay thank you okay well as I said depends it's pretty mole dependent so the answer is somehow mole dependent now if your state entering into your re-completion the re-completion that account for you one loop realization or the two loop realization you have is a standard mole singlet then you I would say certainly can do it now if your state does not have does have actually SU2 cross U1 quantum numbers then in that case whether you can or not generate a sufficiently large B-symmetry will depend upon the mass of this new state again using the argument I gave before it depends that value the value for that mass depends upon the temperature at which this value is the couple now with current with current measurements the value we have for the Higgs mass you can calculate the temperature at which this value is the couple that temperature is about 140 GeV okay so you have to guarantee that your state generates sufficiently large leptin asymmetry above that value now if your new state the state you have in the loop or in your one or two or whatever loop you wish to have is such that is kept in thermal equilibrium close by to this 140 GeV or even below then you know that this mechanism doesn't work as I said this basically implies the other way around argument implies that you can place a bound on the state below which you are not able to address the bionysymmetry puzzle of the universe through leptogenesis in that scheme okay perfect so it's still so I don't know more questions otherwise we have the last one here in the queue of questions so this one is more or less inspired with dark matter in the sense if this can these scenarios also are compatible with extra hidden or dark symmetries like you want d-l-dark that correspond to the dark sector kind of inspired by asymmetric dark matter or the opposite asymmetric dark matter model inspired by leptogenesis who's asking that me also so you were the only one attending to my seminar they're thinking okay so when you when you speak about this is an argues you are including type 1 c so are you only speaking about type 1 or type 2 or in general are you speaking about in general in general well whether you can I mean the main point is the following is that there are three things you have to satisfy you have to satisfy c-p violation, lepto number violation and departure from their molecular as soon as you can guarantee that you can embed your scheme in a larger scheme much more things so for example you can't think about scenarios of looping these neutrino masses where you the same symmetry that enables having the neutrino mass in a way that's at certain level it stabilizes one of the degrees of freedom you have there so that state in principle like it happens in this cotidetic model that state will play the role of their matter and then as it turns out to be in this cotidetic model as well you have the right hand neutrino out of which you can generate the lepto symmetry so the cotidetic model is from that point of view a benchmark model with which you can argue that you can always construct scenarios where you have leptogenesis and neutrino masses in a single shot very interesting if you find an appealing model let me know we can work it out yeah let me see just in twitter if we have some question it seems that we don't have it in twitter I don't know the rest of the people in the hangout if they want to address the last question well there was a question by this person yes I don't know if he can if he can add an extra comment on his question to make it more I guess for the stuff that was written I guess he was thinking in a model in which you only have three body decays for some reason two body decays are suppressed yeah ok you can think about scenarios of that time but certainly the fukujita scenario is not you have three body decays you can think about scenarios for example you can now it comes to my mind that you can think about the c-mol so in the c-mol you can construct you can draw three body decays which generate the leptonosymmetry and you can show that in that case as well you can generate sufficiently large leptonosymmetry so this is something that was done by tomahan b if not in the 90s late 90s probably early probably about 2002-2003 or even before so he studied that problem so of course you can think about scenarios where you have three body decays what will be the difference well if you have a three body decay and you compare that with the case where you have a two body decay reaching the condition of being decoupled of reaching of reaching the condition of being out of thermal equilibrium is different because of course in a three body decay you have an extra suppression factor determined by phase space so if you wish you can think of this three body decay as a two body decay where you rescale your decoupled copies in such a way that your decoupled copies are smaller this means that basically by a two body decay your states will decouple before than in the two body decay case because basically if you have something which is two body decay with a copy which is 10 to the minus one and two body decay with a copy which is 10 to the minus four if you stick to this language that people like to use weak and strong wash out this means that moving from the two body decay to the three body decay is equivalent to moving quotation marks from the weak wash out sorry from the strong wash out to the weak wash out that's the only difference so your states are less strongly coupled to leptons than they will be in the presence of just two body decays that is the only difference and this statement in my opinion is completely mold independent doesn't depend upon the mold you are dealing with ok very in fact this is a topic that is worth to know let the genesis know what is happening in the early universe so let's see there is no more question here in twitter and last chance for the people if they want to ask if not I guess we can start to close this session so we acknowledge Diego for this very interesting webinar and for the people that is looking for this video already in youtube you can make comments and leave it here and we are going to make this comment to arrive to Diego if you want to contact him or start to collaborate with him so for what I am concerned so we can stop this webinar here and just going to present this is the ending of the webinar and these are the people that are behind the team so I hope you enjoy this webinar and we are going to see you in the next one that is in principle is going to be like in two more weeks so have a good day and see you soon