 let's see we're going live okay we are live all right so hello everyone and welcome once again to the Latin American webinars on physics I'm Joel Jones from the PUCP in Peru and I'll be your host today this is webinar number 95 and we're having Lucia Duarte as a speaker who is a professor at Universidad de la República in Uruguay. Lucia did all of her studies here at Montevideo with a joint PhD between Universidad de la República and Universidad Nacional de Mar de Plata in Argentina. So today Lucia will tell us the latest news in effective theories with heavy neutrinos in particular regarding them leptome number violating processes so of course we're very happy to have her as a speaker today. Now before we begin let me remind all viewers that of course you can ask questions and comments using the YouTube live chat system and these questions will be passed on to Lucia by me at the end of her talk right so great having said that let me pass the microphone over to Lucia. Okay so thank you very much for having invited me to the low physics and I'm very excited to be here sharing my work with you so I'll start sharing my screen oh I think okay so did you see it well you have my slide okay great so well this is my talk, Marjorana Lucia, sorry you're having some issues with your connection we didn't hear anything that you said can you hear me hello oh oh this is strange we've been talking to her for about half an hour without any problems okay so let's wait a minute until she reconnects in the meantime oh there she is she's back she's back she's coming back hello do you see what happens with my connection sorry this is very strange because we're talking to you for about half an hour without a problem yeah now we did okay great so quickly started the beginning because you started sharing and then it was it was okay so let's let's try it again let's try again and share my screen now so I was telling you this can you see me down can you hear me yes okay great so I'm gonna talk about this Marjorana and Trino's with effective interactions in the case this is a joint work with Oscar Sampacho who is my advisor at University of Marredlada in Argentina and we've been working in this in this effective theories for many years now so it's a joint work with all the team in Marredlada and I'm gonna tell you about this paper we found this last year and I hope we get to the new results I'll try to to to have them in the archive next month so is it all right are you you you get me well everything good okay perfect so I will start my presentation telling you my outline I will to move this over here okay so let me start with the motivation I want to make the case for oh sorry sorry I have trouble with the okay now I'm on Anna so I have this signs in my in my screen so I'll start to motivate my talk try to make the case for the standard model the Trino effective theory so let me start to fix my notation as you all know in the standard model uh firmness acquired our masses by interactions with the Higgs bell and you get the the Yukawa Laurentian term where you have this this connection with the left-handed and right-handed components I created it for the for the charge leptons here and as the neutrinos don't have a right-handed component in the standard model they don't get masses this also our violation not between the families not global and in fact uh this flavor change from the the outside neutrinos can be explained by by the mixing with the massive propagating states you you describe this this mixing with the ponticorbo matrix and you can explain installations with masses for the flight neutrinos that are very low point one electron volts so we all know this this this things this is just to remember what we are what we're embedded in and this makes us have the standard model need to incorporate masses somehow and the easiest and the most popular way to do it is the CISO type one mechanism so you incorporate this right-handed sterile field so you call them sterile because they don't interact with the with the standard model interactions and you can write this like Laurentian I call it LU you write once you incorporate this right-handed terms you have a Yukawa term for for the neutrinos and as they are sterile and if you don't uh if you allow for let the number violation you can add this this major an amassed term for for the sterile neutrinos so when you write the the matter uh the the matter the terms for the neutrinos you diagonalize them and the three sterile neutrinos as I'm showing here you will end up by having six massive states which are majority furnace meaning that they are down at the particles and let the number violation is allowed so you get three light massive states and three heavy massive states and it's called CISO because the more massive the heavy ones are the lighter the others so when you constrain this mass to be below 0.1 electron volt or something like that you can write the mixing between the active and the massive states and the thing is you get this relation for the mixing that is we call the CISO relation and if you do this this mainly you end up with a mixing that is it's really really small so there are ways to avoid this by by having new new symmetries for instance b minus l symmetries in in in the in this Lagrangian you can you can add some kind of of lipton number and and conserve it somehow but if you do this mainly you get really uh a very tiny mixing so as this mixing drives the coupling between the heavy states understand all particles the thing is that if you don't do something if you don't impose some other symmetries you will end up with a mixing which is too long to explain lipton number violation and we already have constraints they are very stringent experimental constraints on on these mixes here they call V this is a plot by June last year that can be compared with what we're talking about so for instance you have this only beta beta limits from nutrient is double beta decays and so on so this mixing wouldn't be the guy i would blame for lipton number violation what i mean is if you were to discover lipton number violation maybe you have to explain it by something else and that's what i want to talk about today so you can tackle this topic by saying okay i have these right handed fields and i want to study their terminology and i want to do it but in a more independent way so you can say okay let's build an effective field with these fields and the standard model fields then what you would do is to have the standard model like engine then add the the c-sol like engine and then you can add more operators with with higher dimension that to the to the elemention that would parameterize this other new physics beyond the mixing that that could help you explain lipton number violation and whatever you could find the experiments so i'm showing you here the dimension five operators you can add this has no no right handed neutrino this is the one known by the operator it gives you a much more mass for the active and for the active neutrinos and you can also get interaction with the Higgs in fact then you have this other operator you can write with the right-handed fields this gives you also a contribution to the 100 madrana master that we were talking about a minute ago and it also can give you an interaction with the Higgs field so many people started studying this because it gives you an interesting phenomenology you can see this table a couple of times and well many people are starting now to study that and you also can have this other operator which gives you a tensor interaction between the right-handed neutrinos and the photon and see both of fields here in the in the u1 field strength so that what that's what you can make a dimension five but what i want to tell you today it's a very easy description our description with only one majority neutrino and concerning only effective interaction so let me come back i just want to show you that this operator here is anti-symmetric in the in the sterile index so you need at least two right-handed fields to to have it if if no advantage is complete so what we're going to do is to consider only one hey state only one madrana state and only its effective interactions so this is a benchmark scenario which is very simplified but helps you to gain in street addition on which kind of things you you could find beyond the this is all mixing so we discard the mixing term in the original normalizable Lagrangian say you can put this this coupling space you cover couplings to zero and we will consider all the one massive state so when i say the end the heavy end it will be the right-handed it's the same guy if you only have one and you add a madrana mass so we don't consider it as a madrana park then you can discard this all five and five contribution to the to the mass to the mass and then and we absorb it in the physical mass and because this car distance in fact we will not be discussing hicks interactions here because we were concerned with bdk so that's why i'm not taking them into account but this is this is useful to gain intuition so what we will do is having the effective and this effective theory Lagrangian which includes this animal and tens with an engine in the end higher than six so i'm gonna try to tell you more about the the apparatus you you could when you when we use these small so we have this effective right those with the madrana and we have interactions with the end and the scalar vector bosas here's the the interaction with the hicks field you can interact with with the derivative here it gives you an interaction with the set i have this verdict here to show you then you can have this kind of off term with with with child leptons this would give you nice verdicts between the L, W's and N's these are victorial interactions then you can have four ferment terms also vectors and scalars these parameterize many kinds of new physics that can be written in the end in in in this way and you can have long loop generated operators they give you a tutorial coupling again between the the photon and the set and the madrana and so they give you this vertex we will be talking about right now so let me show you more deeply which kind of interactions we will consider so we have this NL field interaction that gives you this kind of vertex so we will be concerned by interactions with quarks and charged leptons so you have this this kind of of of vertex here and then we will be concerned with the four fermions interactions we have victorial ones and scalar so if you want to check more about the these operators and a real bosas in a web you can you can check these these papers here so beyond the three level generators i was saying we have the one loop generated operators these are suppressed by a loop factor in fact and they give you this very rare interaction between the heavy neutrinos like neutrinos and photons so this is our pink element in the room if you include these operators you have this decay channel of gene and this will change things in your phenomenology and it's very surprising it gives you new things that we will be discussing right now so you have this width of the end the heavy end going to light neutrinos and and photons other people have discussed the the constraints on this kind of operator and try to work with this and i i recommend you to check those papers and now let me go to tell you how to put bounds on the on the couplings of each effective operator so when we started a life many years ago we we took the sunsets we said okay we have this dimension six term giving you these verdicts here and you could compare it to the one you get the similar benefits you get with the when you do the mixing in the syso one so we said okay let's let's compare the the mixing in the syso with our our alpha effective couplings so we said okay as we have bounds on this interaction very stringing bounds on these interactions at least we should put bounds on our operator that are equivalent so if i'm if i'm putting this new interaction i have to bound it because i already know that we have constraints on this so what we did was exploit existing bounds on the mixings taking this um this comparison this is the dimensional quantity that you have here you see you have the the coupling the the squared and two times the squared of the new high energy scale high energy physics scale you're introducing in your in your effective field theory and we did that for every operator and all finalists so you have this the electoral family i and then you say okay this is my alpha i for for any operator so it's not only this interaction and comparing but but everything and you we started exploiting it exploiting the bounds you have on the mixings so the first bound you have the strongest one is the one from your journal is double beta decay you can see it here uh there's the limit from there that we're using can't understand because it's more strict yet and you can bound the the first family operators that that give you a contribution to to this process so again you can use the bounds on the neuron and tau couplings and the thing is that you could compare in all the mass scale uh with every experiment but the thing that happened is that as we have this new channel this neutrino photon channel we we couldn't get the bounds uh translated so easily because not every experiment would would function if you have your majority to to to have this decay so in the end we started considering the the doffy bounds here which are which are compatible with having a on magliana and with this decal channel here's the diagonal and you can see that it it fully covers the the branching for low masses now compared to to the case to to leptin to leptons and and permanence so this really changes how you how you're studying your your phenomenology in fact if you add if you allow this channel to be on so this is if you let your tensor operators to be on if you if you let your tensor couplings to to be non-zero the width this normalized width to this to this coupling here it changes a lot so here i have a plot if you let the neutrino decay to photons and you see this is more than one other magnitude to bear to the width you get if you don't let this channel to be on so this will be something that we will be taking we will have to take care for it so i will move and show you again this comparison between the physical scenario and what we are having so we have these these sets of operators we treat them for the numerical treatment so you have sets one and two and four and five so in the first three sets you put on your tensor operators that allow you to have this photon neutrino decay and then in the blue ones you let on the vector couplings your vector operators and in the green ones you have your scalar couplings and this way on the plots that i was showing you before and i want to compare with what you do which is the same thing here when when i normalize the comparison with the width you get in the season model when you put your mixings all equal to one so if you compare here you have more than 10 to the minus seven and here have a bit more than 10 to the minus nine so it changes it changes your lifetime for for the end so that will have consequences also sorry here you can see you can put a coefficient in front of each type of of decay you can have in the season model and these these coefficients are already very constrained so they are in the best case 10 to the minus side so that will be a difference for us so now let me go on to tell you about this and maybe it would be the case i i wanted to to show you now so what will be what we will be starting is a bbg to turn left which can be a muon or from the madrana m and then this guy we wouldn't consider it can be gay to this neutrino photon interaction and final step we've been talking about or you can let it go to a left and and the pion so first i will tell you about the last year results we have exploited bounce from bell and from lhcb on this on these processes to translate to bounce on our effective couplings and then the working progress this year has been using the bell tools prospects to measure this beat to tau and neutrino decay which can be confused with tau to n decay if the n escapes the detector to see if you could tell the difference between the standard model and the effective theory measuring the tau polarization that's one thing we we were trying to do and we also have to we also have new bounds from from this decay and we have this uh forward backward asymmetry between the faton and the leptin here this is a block from from the bell to physics book so we can construct an asymmetry between these two guys and see what contributions you have for when when you include these effective interactions so i'll start telling you this before i go to the results i want to show you part of the calculation here you have the vertex with the b decaying to n and the leptin you have to calculate this this amplitude and you see that when you when you do this as the b is a sinus collar you have only this kind of currents alive say the surviving ones are the sinus vector and sinus collar terms so when you calculate the width of the b going to uh charge leptin which in this case could be the tau or the moon and the matriarchal triangle you will get something like this i have simplified it for for you but what i want you to see is that you have kinematical non-dimensional terms but you have the scalar squared terms which have a quote mass denominator here so this factor is is it's more than one is like six or seven so this really enhances the scalar interactions compared to vector ones so here you have these coefficients with the with the scalar coefficients for s1 s2 and s3 operators and you will see that that all our numerical results will be will be interpreted in in this way we have the enhancement of the scalar contribution coming from from this guy the same will happen in the end the case of biomes and and leptins so this is something i wanted to come in before showing you my results because we'll find this is this is something important so let me tell you what we found first we can see that this radiative leptinic b to new new gamma decays we have these bounds from bell that haven't found it so haven't found the the this decay yet this is easier to measure than the non-relative decay because if you only have news this goes like the mass of the new square so they are more measurable that only the new channel this this radiative channel but but it's still not found so they have this bound they they give you on this uh integrator branching ratio understandable value is more or less five times to five times 10 to minus seven you have to integrate this branching this is why it's called a partial integrated branching fraction between the available energies of the photon so you have a lower energy cut that we take it to be one gb because that's what they got there and this is to ensure that your treatment of the qcd approximations is okay to the to the maximal energy so this is kind of the the sum amount calculation and we do the same but with our effective theory so you consider the width of the b going to mu one and n and then the branching of the n to the training of some photons which is almost one in in this mass regime and when you do that you you get to use this bound to get constraints on your mix and so how do we do that we fix all the values of the of the couplings the scalar the vector and the tensor couplings to the same number and we parametrize it and consider this alpha and translating it to u square and you then get all your quantities depending on the mass of the n and this u square thing so when you do that you can find for each mass which are the values of u square that let you be below the the experimental bound and this is how we construct this this plot so for each mass you have an upper bound for the u squared and this is made for each coupling set as i told you before so as sus was explaining you we can put better bounds on the sets that include the scalar couplings so it said once is it has vector and scalar operators on then set three songly scholars and set two songly vectors here of course you have all the cleansers couplings on because you need to have this decay working and you can translate again this u square this u square limits into alpha limits so that's a first kind of bound you can have directly from from from bdk's we also started the bounds you can get from bel from sorry from lcd so i maybe you remember but uh years ago lcd gave modeling independence on the decay of bs to millions and and pi this is a little number violating uh process they were doing it for the sissot model but but they gave this this kind of plot which for each mass they had this this lifetime for the end and this this changes their detection efficiency so they have different plots different plots with with upper bounds for the different lifetimes of their end and they had made an interpretation for the the muon maglionics in sissot type one which was criticized by shubin peskin afterwards so this is the plot by by shubin in this paper they had this was the original lcd limit and we had the revised limit because they were using a very nice model for for this decay so when we saw that we said okay we can do this and we can use these bounds to to put them on on our effective theory so we calculated the bdk to try and and new and then let the the end you get to find some news and we will we calculated the branching fraction on that for each mass we all uh we do the same that we did in the last in the last slide i would pick the fix on the a first and then you have the your lifetime here is our translation of the bounds from from an hcd and then you can get a bond in your in your mass and new square plane so here are the bounds the black line is the bounds for u square that that shubin peskin got and this our our bounds on our interpretation that is u square so again if you let the maglionic tree are to also include in the in the total width here the tensor operators you have these bounds in the sets we call one two and three set one includes scalar vector and tensor operators set three includes just scalar and tensor operators and set two has only tensor and vector operations this is why the vectorial bounds are are weaker as as i was telling you before and you can do this same for the set where you don't consider the the tensor interactions so you don't have this decay to the to the tree no and for them and you see we can put much more stringed bounds in this case but also of course this color this color bounds the bounds of the scalar operators are tighter than the ones in in the vectors again this is the core the curve by by shubin so let me summarize what we had we have this summary of effective dvk bounds so for every set we have found limits on this alpha and and plane and you see these are the bounds from the muon radiative decay here and here you have 10 to 1 so this is 10 and this is one these are very very low this is are no no no much stringent but then the bounds from the b to muon and pi decay are much better if you if you translate them to the alpha and then plane so this is what we got in paper last year this this bounds could be compared with the people from with bounds that other people are are starting to have now using this kind of simplified scenario where we are using there are some differences so they're still not fully comparable but but people are starting to to work on this that makes me very happy and then i will try to show you the new results that are yet unpublished i hope i can i can make it for next month to the other guys so let's consider the d to tau and neutrino decay this could be confused of course an experiment with the effective decay to a heavy end if this guy escapes and detectives so uh there's no single observation with more than five sigma from my experiments of of this decay right now but there's a combined limit from the lemma bar so you have this branching this experiment i'm not sure of the branching in this number and we said okay we first could try to use it to impose bounds on on our couplings so we calculate the theoretical contribution adding the standard model and and the work and the and the madrana contribution and then we again translate this to bounds on the on the m and alpha plane consisted with the the theoretical branching not changing too much from the experimental value and assuming that you need this n to live more than 10 than 1000 picoseconds so that it escapes and detectives so for this lifetime to be as high as this you need to you need to kill your tensor operators so the only sets that you have you you can use is this we were calling four five and six where you have the tensor operator off and and you see here the means you find here's the car below where you can have uh in the in the m and alpha plane the the below where you the lower zone where you are consistent with with these conditions and i have plotted here the hcd limit to to compare so we get more the hcd limit is taking more more stringent than this if you only consider the couplings to the third family you get this car so the the area is much much bigger but if you consider all the the three family couplings you you end up here and the same you can do for your set so this set has vector and scalar interactions and this set has only scalar interactions as i was saying the vector only it gives no interesting bounds because you you get uh you you have some loose numbers so you don't get a nice plot that's why i'm showing you this and the other thing we wanted to do with this decay is see okay what if you measure the tau alarmization can you can use the period can you compare it to the the standard number if you did the standard amount of calculation it gets you sharp one and then you say well if you do the calculation for the effective theory you get uh lower and you get a lower final tau polarization so we say okay can you measure that okay could it be seen somehow sorry in the experiment and then you have this this p tau the level curves this would be 0.95 or 0.9 so if you can tell the difference from the measure polarization to them to the standard number one and we find well this is not so encouraging as we first thought because the alive region is down here for the set four and for set six so it's not that you will be able to distinguish it very much if you could measure this this decay for instance in belt two so we have to look for a better environment maybe other other experiments to to look at this and then the last thing i want to tell you is a nice result that you will get studying a forward backwards symmetry in this b to muon neutrino further decay so if you consider this this is symmetry between the charge left and and photon and you know it's a simple forward backwards symmetry measuring how many times they go in the same direction or or the contrary and if you calculate this for the standard model this is not a little number violation the violating decay because you can see if this neutrino is a neutrino or anti-neutrino so you have a kind of interference between the left and number conserving and the left and number violating final state so if you calculate it in the standard model it gives you a number that is below zero you can see it easily in the case where the photon has is matching the maximum energy because you see that when that happens in the standard model it has to come backwards with the with the muons because they take the maximum energy when the other two guys go go the other or go in the other the opposite direction and if you make your calculation in the effective theory considering the decaying like this you can have your contribution added to the standard model one and we made a numerical treatment here that in which we considered the scalar and vector interactions to be summed up and divided by two and so that's how we get our tensor coupling this is just to be able to make two replots on this and so for instance here I am I'm showing you the standard model values which are the dots and then for each major and a mediator mass you can see the full contribution so this is the the adding up of the standard model and the effective result and what's interesting is that the when you include the effective interactions you get a less negative values but you have a contribution that it's on for for an interval in the photon energy that can be explained by by kinematical reasons in fact you can calculate the boost of this guy and and calculate the angle in the purest frame and this depends on the velocity of the of the n and it's its boost factor of course it depends on the energy of photon and the animatronic mass so you can make this calculation and get this plot for each mass you can see that the contribution for instance let's let's see the the 4 g d car the contribution starts to be more positive so not that negative when this cosine starts here this is one point something one point five something which is right there and then it it goes on contributing to less negative numbers until it gets to negative values of the cosine again so here is where the contribution stops and the same thing happens for for every value mass so that was interesting to discover because we first had this plot from our Monte Carlo simulation and then we say okay can we explain that and it was something nice to define and we still can compare the scalar contribution here I was putting the scalar operators and the vectors off and you can compare with the only vector contribution which is much much lower this is the same effect we we've been finding due to this this decay that I was showing you before and you can see that if you plot the distance in sigmas from the standard model values which would be alpha scalar and alpha vector equal to zero for each mass you can find that of course these curves are more how you say wild in the scalar direction and vector direction so this this you can understand again from from the enhanced scalar interaction so this is all I wanted to tell you I'm going to summarize but not summarize because it's been too short so I just want to give you my message that the standard model treat effective theory is a nice moment independent way to get info on possible metaphysics beyond mixing contributions to the heavy end phenomenology so we could try this this study in a in a more organized and systematic way to constrain these operators and there are lots of parameters to be explored yet so join us and we can tackle this theory in a more systematic way and okay thank you very much for your attention okay thank you very much uh so so so I'm sorry Lucille that I had to turn off your video just to make sure that the connection was was was okay you can try and turn it on back on now if you if you want okay you kind of start because the host has stopped you that's what it says oh really okay so let me let me see if I can if I can I can stop sharing my okay here all right great okay so super so thank you very much for the for the talk it's been it's been very very very interesting it's been so fast I'm sorry well given the time constraints I think it was perfect okay thank you so so um I don't know if there's any there are any questions from from the audience I have like three questions or so but okay let's say let's see if any if there's anybody else here that would like to start okay so so I'll start okay so can can you go back to to the slides where you showed those little uh those new contributions um for for the asymmetry yeah yeah yeah exactly okay I'm gonna how do I go back okay here yeah yeah exactly so so so I said do you want me to to put it on this screen or or yeah yeah yeah you can see it a bit better yeah okay so so so I find this this very interesting you say that that extra contribution comes from from the additional uh production of the heavy neutrinos but yeah that is a kinematic kinematically constrained to particular values of photon energies right yeah that's why we have those little that's depending on the end mass we have the allowed energies for the photon right so outside of that region one would one should get a roughly that the standard model yeah that's it which is what one sees like for instance on the on the on the orange curve the orange curve yeah that that's that's that can't be distinguished from this and I'm all until you enter through this so this allowed some so so this is for IGD right so what happens with the red curve there the red curve deviates from the from the central values of the the red curve down there yeah it deviates and in fact the thing is that it gives you a more negative contribution because you see here that when the major animus is tgv you get all the time for for all the photon energies you give a negative number of cosine theta so this enhances the value of the standard model and moves the the symmetry to lower values I see I see that's the same thing that happens with the green this is the current here yeah and this is the same going on with the green curve when you give this cosine negative value it goes to more negative values than the standard model that was very interesting to find yeah yeah yeah I find it very interesting okay because in the when we started plotting we say okay what are these bumps and and finally we we say oh well it's the end boost so that's it what changes with the with the model and with the with the the values of the couplings is the amplitude you know you get more I was showing in the next slide when you when you change your your your couplings to values that contribute more to to separate the the value from the standard model value then you have a sphere amplitude that's it but but you can understand it that way great no super very interesting indeed so let me ask one more question before reading all the all the all the questions on the on the chat and and letting the other the other one so at some point okay so so so you you showed us results for a heavy neutrino decay into a photon and a light neutrino that was your your work from from your last paper and then at some point you you you switched the decay into a mule and a pion right yeah two mules and a pion right right exactly but but that right so so the final state was to yeah two mules and a pion right so um the question there is that at some point you do mention that the branching ratio into into photon and neutrino is is is dominating yeah but then in the other case you don't have that so what are you doing are you just turning off for that I can turn if I turn off the tensor couplings I don't have this this this neutrino photon channel yeah so you're turning it off for that yeah if I turn the let let me go to the slide the thing is you you you have you always have this channel but what changes is the the total width because if you let the the the photon channel on the width it's much bigger so this this lowers your value in this in this channel that's why you get more stringent values of the of the for more stringent bounds for the sets where you put off the the tensor operators right so so depending which coupling you have on you have different observables of course that could yeah that's it but the the difference is made by if you have this channel on or off great super super um so I don't know if there's anybody else in the in the audience who would like to to ask questions we have Roberto Nicolás we have a guest Leon who might want to ask questions too yeah I have a small question is it yeah is it possible because I don't maybe I didn't get this part but can you get other observables related with pi and zero or something like that like yes of course the same procedure I mean that the same operator impact many other operators impact many other observations yeah in fact we were trying to see what happens with this this anomalies in bk's also you can contribute to many many other many other observables so we we did it because we started with these bounds because the bounds were tight and we wanted to see what which bounds we could get but then discovered that you can try to study more and more observables in in bk's and when the phenomenology is is wide so you can do many things we we have been studying the production of these ends with the effective theory in my phd and then we started to study bk's but but these channels contribute to to many many other levels that's why I say that there's much place to exploration of this of this effective mode okay thank you great uh so so let's first go now now go now into the the questions from the chat and then we can go back to to questions from from all of the other listeners so let's see um first you have the question by a Diego Restrepo okay here we go yes I'm on the call to something so what is the relation between the right-handed heavy neutrino mass and the lambda and lambda well I didn't mention that but uh let me go backwards so that I can go back to the start what lambda is what lambda is so lambda is the this this high energy scale you consider for your effective theory so one could say okay you have to the first thing you can think of is that okay I well I want to relate lambda directly with the mass so that this is the scale where I can produce this majority neutrino but then you find that it could be this game where you have these new interactions because each operator will be will have to be mediated by something in the in the UV theory you consider so when you when you think about that you know for instance you have this this four fermions operators and the vector operators are mediated by by vector by vector stuff and the scholars are mediated by scholar stuff for instance that this S3 could be realized by the mitigation of a laptop work so depending on the UV complete model you can say okay I can relate this lambda scale to the mass of each mediator that's why we don't treat it to be the the end mass because the end is a is a low energy degree of freedom in our effective theory we are not waiting it out so it's not his mass that should be related to the to the lambda scale in principle super I hope I hope the other side is okay so let's see we have this not a question but this is a comment by Mark Bartholomew who is having who is thanking you so much for the talk and saying that great thank you really rocked okay and I'm gonna thank Cardoso is also thanking you we have a person who also is saying that it's a nice talk and would like to know if in the vertex for the right-handed neutrino decay do you integrate one loop of Higgs field wow wow which vertex I guess he's talking about the tensor terms so I will move to this like can you see my slide there I have to share it fully so here what you have is just that these operators can be generated in the high energy theory you'll be complete theory whichever you like have to be constructed using loops of whatever the fields are in the loops so we are we're not specifying what's going on inside that but yes you can have the terms with the Higgs beam here that those are the ones I'm using but they also give you interactions with the Higgs and all that so in if you want to go to see this paper is where where I write the full energy and you can see all the all the interactions that you can have that those operators give you because there are many arrange in terms so we were concerned with this because this is the the line of graphics more the phenomenology I don't know if I'm answering the question well in any case Percy can write on the chat there's a slight lag between between the transmission and what one says on on YouTube so so if if it wasn't clear then he has a chance to ask again so and so any other questions from the participants here I have one more but I'm going to wait okay okay so so so in the in the the result you presented for again heavy neutrino going into photon and light neutrino if you have used instead the dimension five operators I think who too heavy yeah yeah of course I know what you asked me that yes of course so let me move backwards say if you have if you have this dimension five guy if you have two right hundred neutrinos now say you have two indices say one and two for instance you you you ship this operator this comes with only one lambda suppression not not lambda so this would be a higher contribution to to that effect if you had two neutrinos so this gives you a tensor coupling a magnetic coupling between the two headings and the photon and all your mixings and the set also so you have bounds so I forget right but but it was it would also give you a higher interaction between the neutrinos and the photon so you could bound them more stringently also and and this will give you a very nice feature so yes but as we are only two in one sterile neutrino that's to avoid all the mixing because it's it's kind of it doesn't let you see the effect of the of the new interactions so that's why we don't consider it it is here but it also helps you to see some beyond the mixing but if you have mixing then you can have that operator and that would give you a higher contribution so that's okay yeah of course great super I'm many more things great so so so Percy says that yes you have answered okay so he's happy okay I have another question in the chat we were on a roll okay so the next question is if from Jonathan Cardoso is asking if there is a some relationship between these neutrinos and the b meson anomalies well they we haven't studied it but there's many people working on that so I'm excited about those guys in the paper I hope I finish for next month but there are there are contributions there's a new paper by Antonia pick in fact that that how that have tackled that issue they they have a low energy effective theory with with right-handed neutrinos something very similar to this and they they do they do some calculations and get some bounds they're not easy to translate to this word because I'm in a very simplified scenario but but yet it would affect the the anomalies so that's something people can go on starting right super so uh okay so it's been an hour already maybe we should maybe I'm there maybe there are some urgent questions still okay okay so I think we're okay there's nothing in the chat either we've given a little bit of time so perfect so there shouldn't be any lag now okay so great thank you okay thank you very much no nothing more from that from the chat okay okay so thank you thank you very much Lucia for for for this talk it's been great having you around and before we log off I would like to remind everybody that we have the next webinar now in two weeks by Sean Hart all right so please don't miss it it'll be very interesting right so thank you once again and see you on the next webinar okay see you thank you guys