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Impact of LHC Higgs physics and EDMs on Baryogenesis in the Standard Model EFT with dim 6 terms

Time and date: Tuesday June 2nd @15:00 (CET)

Speaker: Marta Losada (New York University Abu Dhabi)

Title: "Impact of LHC Higgs physics and EDMs on Baryogenesis in the Standard Model EFT with dim 6 terms" 

Abstract: In this talk I will present the study of Higgs boson observables at the LHC and their impact on electroweak baryogenesis in the context of Standard Model effective field theory with the inclusion of dimension 6 operators of Higgs and fermion fields. I will also discuss how these new terms can generate an electric dipole moment of leptons and thus add further constraints to produce the baryon asymmetry. I present the main results when considering a single fermion flavor term or for combinations of two flavors. For each case, the results of the identification of which observables constrain more severely the new terms and the interplay of the complementary constraints to identify viable regions of parameter space is also presented.

Slides: files/HIDDEN-062020.pdf

Video: https://eu-lti.bbcollab.com/recording/ab4c6ea3ed464190a4862c9b76afd04f

 

The Axiflavon, Jure Zupan

Speaker:  Jure Zupan (Cincinnati U and CERN)

Abstract:

Solving the flavor problem of the Standard Model with a simple U(1)_H flavor symmetry naturally leads to an axion that solves the strong CP problem and constitutes a viable Dark Matter candidate. In this framework, the ratio of the axion mass and its coupling to photons is related to the SM fermion masses and predicted within a small range, as a direct result of the observed hierarchies in quark and charged lepton masses. The same hierarchies determine the axion couplings to fermions, making the framework very predictive and experimentally testable by future axion and precision flavor experiments.

To see a video recording of the session, click here. Slides are available here.

 

The Fermi GeV Bulge Emission: Dark Matter Annihilation or Millisecond Pulsars?, Christoph Weniger

Speaker:  Christoph Weniger (University of Amsterdam)

Abstract: 

I will summarize our current knowledge about the GeV bulge emission. A leading astrophysical interpretation of the emission is that it comes from thousands of hitherto unknown millisecond pulsars (MSPs) in the Galactic bulge.  I will discuss in some detail a wavelet fluctuation analysis of the gamma-ray emission from the inner Galaxy, which we did recently to test this hypothesis.  We found strong support for the MSP hypothesis.  However, systematic uncertainties remain large, and a clear detection of the bulge MSPs in radio observations will be necessary for a solid confirmation.  If as significant number of MSPs is found in the Galactic bulge, this will reduce, and possibly eliminate, the need for more exotic explanations in terms of dark matter annihilation.  I will close with our plans to search for these sources in radio, using MeerKAT (planned for 2018) and telescopes like the GBT and the VLA.

 

 

PDF:http://reunion.uv.es/p2tqdzo6kyy/

WEBINAR

CP Violation, Baryon Oscillations, and Baryogenesis, Ann Nelson

Speaker:  Prof. Ann Nelson (Washington University, Seatle)

Abstract:  I discuss CP violating oscillations of neutral baryons into anti baryons, and propose an experimentally allowed scenario where some heavy flavored baryons oscillate at rates which are within a few orders of magnitude of their lifetimes, while the flavor structure of the baryon violation suppresses neutron oscillations and baryon violating nuclear decays to experimentally allowed rates. I describe a scenario for producing such baryons in the early universe via the out of equilibrium decays of a neutral particle, after the hadronization temperature but before nucleosynthesis, and the prospects for baryogenesis. 

Rethinking the origin of neutrino mass: the role of gravity, Gia Dvali

Speaker:  Prof. Gia Dvali (NYU and LMU Munich)

Abstract: We discuss a generic  source of chiral symmetry breaking  in the standard model fermions in form of gravitational anomaly and its role in generating neutrino masses without the need of other sources.

The Beryllium Anomaly and New Physics, J. Feng

Speaker:  Prof. Jonathan Feng (University of California, Irvine)

Abstract:  Recently a 6.8σ anomaly has been reported in the decays of excited 8Be nuclei, which can be resolved by postulating the existence of a new weakly-coupled, 17 MeV boson. I will discuss the experimental results; new physics explanations, focusing on dark forces and gauged B and L symmetries; and prospects for future experiments. 

Gravitational Waves as a New Probe of Dark Matter, B. Dev

Presenter:  Prof. Bhupal Dev (Washington U., St. Louis)

Abstract: A dark matter (DM) halo intervening along the line of sight of a gravitational wave (GW) signal could induce a change in the speed of GW. We show that this change of speed is observable with the current LIGO sensitivity for a class of ultralight DM models which could form a Bose-Einstein condensate (BEC) in the early universe and behave as a single coherent wave instead of individual particles in galaxies. Hence, we propose to use the deviation in the speed of GW as a new probe of the BEC DM parameter space. With a multi-messenger approach to GW astronomy and/or with extended sensitivity to lower GW frequencies, the entire BEC DM parameter space can be effectively probed by our new method in the near future.

Is a non-standard interaction a solution to the three neutrino tensions?, O. Yasuda

Speaker:  Prof. Osamu Yasuda (Tokyo Metropolitan University)

Abstract: In this work we present a scenario in which a nonstandard interaction in neutrino propagation can explain the three major tensions in the neutrino oscillation data at present. These tensions are: (i) a non-zero best-fit value of the non-standard oscillation parameters in the the global analysis of the solar and KamLAND data which rules out the standard oscillation scenario at  90% C.L, (ii) the measurement of the non-maximal value of theta23 by Nova which excludes  maximal mixing at 2.5 sigma and (iii)  the discrepancy in the theta13 measurement by T2K and  reactors at 90% C.L  Our results show that all these three  anomalies can be explained if one assumes the existence of non-standard interactions in neutrino propagation  in the case of normal hierarchy.  In our scenario the phase of $\epsilon_{e\tau}$ is zero and the most favorable value of the Dirac CP phase is approximately 255 degrees. 

Update on sterile neutrino oscillations at the eV scale, T. Schwetz

Date and time: December 4th, 2017 15:00 CET

Speaker: T. Schwetz (Karlsruhe)

Title: Update on sterile neutrino oscillations at the eV scale

Abstract: In this talk I critically review the hints in favour of neutrino mass states at the eV scale. In particular I discuss the status of the sterile neutrino explanations of the reactor and LSND anomalies, focusing on recent developments. While the situation of the reactor anomaly remains ambiguous and explanation of LSND in terms of oscillations becomes exceedingly disfavoured by the non-observation of muon neutrino disappearance.

Video: http://reunion.uv.es/p3qp5m2g10i/

Slides:  http://reunion.uv.es/p9pv1ka5uiv/

New results from intergalactic medium structures on dark matter nature, Matteo Viel

Date and time: Tuesday November 28th, 2017 @ 15:00

Speaker: Matteo Viel (INFN Trieste)

Title: "New results from intergalactic medium structures on dark matter nature"

Abstract: I will review the current status of Lyman-alpha forest cosmology for testing the dark matter nature with particular emphasis on fuzzy dark matter and thermal candidates

Video: http://reunion.uv.es/p3r1x07s3ch/

Slides: http://reunion.uv.es/p9f87r3wldh/ 

Quantum scale invariance and naturalness, M. Shaposhnikov

Date and time: Tuesday November 14th, 2017 @ 15:30

Speaker: M. Shaposhnikov (EPFL Lausanne)

Abstract: I will confront different ways the scale invariance can be broken in quantum field theory and discuss quantum scale invariant effective theories of particle physics and gravity and their relevance to the hierarchy problem

Video: http://reunion.uv.es/p48ryorun2d/

Slides: http://reunion.uv.es/p14riaio024/

 

The World’s Smallest Neutrino Detector, Phillip Barbeau

Date and time: Tuesday October 17th @ 2:30pm (CET)

Speaker: Phillip Barbeau (Duke University)

Abstract: The coherent elastic scattering of neutrinos off nuclei was first predicted 43 years ago with the realization of the neutral weak current. The predicted cross-section is the largest of any known neutrino interactions; however, the process has remained undetected until recently due to the daunting experimental challenges. I will report on the first observation of this process, newly announced by the COHERENT collaboration—an effort which has major contributions from a large team at Duke and the Triangle Universities Nuclear Laboratory. I will also discuss the importance that coherent neutrino scattering plays in many areas of physics, including searches for Dark Matter, nuclear astrophysics, searches for new physics beyond the Standard Model, and even applications to nuclear safeguards and security.

Video:  http://reunion.uv.es/p1lf9sjctqd/
Slides:  http://reunion.uv.es/p67be0vx9wd/

Lepton Universality Violation in Rare B-meson Decays; a New Local Symmetry?, R. Alonso

Date: Tuesday May 23rd @ 3pm (CET) 

Speaker: R. Alonso (CERN)

Title: Lepton Universality Violation in Rare B-meson Decays; a New Local Symmetry?

Abstract: We review the experimental evidence, recently reinforced by LHCb, of Lepton Universality Violation in rare B-meson decays. On the theory side, in view of a combined $4\sigma$ tension with the Standard Model prediction, the pursuit of a New Physics explanation is in full steam. After a brief overview of the possibilities explored in the literature, we discuss a type of $U(1)$ local horizontal (i.e. flavour) symmetry in our personal quest for beauty behind the madness.

Slides: http://reunion.uv.es/p9hpji14iod/

Video: http://reunion.uv.es/p3grukyhz6d/

Underestimated hadronic corrections or New Physics in B -> K* ll, Nazila Mahmoudi

Date and Time: Tuesday April 25th @ 15pm CET

Speaker: Nazila Mahmoudi (U. Lyon)

Abstract: I will discuss the recent so-called LHCb anomalies, deviations from the Standard Model predictions, in b to s transitions. These anomalies can be explained through New Physics contributions or alternatively through underestimated hadronic effects. Both options will be presented in some detail, in addition to a direct statistical comparison of two global fits to the data based on the two different assumptions.

Slides: http://reunion.uv.es/p91eje3cydc/

Probing nucleon dark matter coupling at neutrino facilities,Claudia Frugiuele

Date: April 4, 2017 @ 15:00 CET

Speaker: Claudia Frugiuele (Weizmann Institute) 

Abstract: I will discuss the discovery prospects for light dark matter  focusing on fermilab based experiments. I will first describe the signal and then I will explain how to deal with the large neutrino background. 

Please join the meeting by clicking this link: http://reunion.uv.es/webinar040417/

In order to avoid audio issues, we encourage the use of headphones and microphones, particularly when asking questions.

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Self-interacting dark matter with light mediators. Constraints and opportunities, Orsten Bringmann

Speaker:  Orsten Bringmann (University of Oslo)

Abstract: Self-interacting dark matter has been the subject of increasing interest in recent years, motivated partially by the reported small-scale discrepancies between astrophysical observations 
and the cosmological concordance model. In this context, an attractive way to achieve both strong, velocity-dependent self-interactions and thermal production is to couple dark matter to light new particles. I will discuss model-building avenues and the resulting phenomenology, with a particular focus on recently derived strong constraints on such models from the Cosmic Microwave Background and other indirect detection probes.

Novel Phenomenology from Axion-Neutrino Interactions, Asher Berlin

Speaker:  Dr. Asher Berlin (SLAC)

Abstract: Dark matter with mass below an electronvolt is a well-motivated scenario in theories beyond the Standard Model. In this talk, I will explore the possibility that a fraction of dark matter is composed of an ultra-light scalar particle that couples very feebly to active and or sterile neutrinos. If sufficiently light, this scalar behaves  as an oscillating coherent field, potentially leading to striking features in neutrino cosmology and terrestrial experiments.

"Axion physics and the 21 cm signal”

Time and date: Tuesday June 12th 3pm (CET)

Speaker: Pierre Sikivie (Florida)

Title: "Axion physics and the 21 cm signal”

Slides: http://reunion.uv.es/p7sdwewv536/

video: 

Searching for Dark Matter at the Cosmic Dawn

Time and date: Tuesday April 24th 15:00 (CET)​

Speaker: J. B. Muñoz (Harvard U)

Abstract: The nature of the dark matter is still a mystery, although current and upcoming 21-cm measurements during the cosmic dawn can provide a new arena on the search for the cosmological dark matter. 

​This era saw the formation of the first stars, which coupled the spin temperature of hydrogen to its kinetic temperature---​producing 21-cm absorption in the CMB. The strength of this absorption acts as a thermostat, showing us if the baryons have been cooled down or heated up by different processes.

I will show the discovery space for new dark-sector interactions, focusing on the case of "minicharged" dark-matter, which can explain the anomalous 21-cm depth observed by the EDGES collaboration.

Slides: http://reunion.uv.es/p283yztwrsy/

Video:http://reunion.uv.es/p46amxtpx7g/

 

Composite Higgs on the Lattice

Time and date: Tuesday April 10th 15:00 (CET)
 
Speaker: M. Golterman (San Francisco State U & Autonoma U. Barcelona)
 
Abstract: Extensions of the Standard Model in which the Higgs particle is a composite state of a new strong interaction can be studied using lattice gauge theory techniques.  Its lightness in such theories has a natural explanation if it is a pseudo Nambu-Goldstone boson arising from flavor symmetry breaking in the new strong sector, or if it is a "dilatonic" meson associated with approximate scale symmetry.  This talk will consider both scenarios in the context of recent results on the lattice
 

Slides: http://reunion.uv.es/p9c1d7roaae/

Gender inequality in science: a diagnosis of gender bias in the scientific field to progress towards a real equal opportunity, Marina Rodriguez Baras

SPECIAL LECTURE

Date and time: Tuesday March 20th 15:00 (CET)

Speaker: Marina Rodriguez Baras (UAM)

Abstract: As nowadays there are no laws forbidding the access of women to education and research in most countries, there may be a general perception of having achieved gender equality in science. This is far from true: women keep being underrepresented in every stage of the scientific career, and studies and statistics show the existence of general and specific gender bias within our field. In this webinar we will go through all the stages of the scientific career to analyse this situation of gender inequality and its causes, as the pervasive gender stereotypes associated to science and technology in our societies or the work-life balance problems that are still mostly assumed by women. We will also consider which measures should be taken to close the gender gap in science, in order to reach real equal opportunity in research.

 

Slides: http://reunion.uv.es/p2v5fkxum57/

Video: http://reunion.uv.es/p5dw8cw4m7b/

Microscopic Origins of the Weak Scale and the Power Spectrum of the LHC, Matthew P. Mccullough

Date and Time: Tuesday March 6th @ 15:00 (CET)
 
Speaker: Matthew P. Mccullough (CERN)
 
Title:  “Microscopic Origins of the Weak Scale and the Power Spectrum of the LHC"
 
Abstract:  I will discuss the weak scale hierarchy problem from a known, but less mainstream, direction and I will argue that the hints we have observed for high energy physics may in fact be a smokescreen, with the new physics responsible for these hints lying much closer to accessible energies.  In the main talk I will discuss recent progress in model building, focussing on clockwork models along with their associated linear dilaton continuum limit, including connections to stringy scenarios.  The second half of the talk will focus on LHC phenomenology for this class of models, including a new search strategy to look for evidence of new physics in Fourier space.
 

Kilonova: an electromagnetic signal of heavy element nucleosynthesis, Gabriel MartÌnez-Pinedo

Date and time: Tuesday February 20th @ 15:00 (CET)

Speaker: Gabriel MartÌnez-Pinedo (GSI and TU Darmstadt)

Abstract: On August 17th 2017, the LIGO/VIRGO collaborations detected the gravitational signal GW170817 originating from a merger of two neutron stars. Shortly after an electromagnetic signal with an intrinsic brightness corresponding to thousand novas was detected by several telescopes worldwide lasting around a week. This kilonova signal has been predicted by theory long before and originates from the radioactive decay of freshly synthesized radioactive heavy nuclei produced by the r process. Hence, it answers one of the long lasting questions in nuclear astrophysics related to the astrophysical site of the r process. In this talk, I will summarize our current understanding of the r process, the answers provided by the recent observations and the remaining open questions.

Slides: http://reunion.uv.es/p1japfpr8it/
Video: http://reunion.uv.es/p9if2as6xct/

Broadening the Searchlight: New Ideas in Dark Matter Detection, K. Zurek

Date and time: Tuesday February 13th 2018 @ 15:00 (CET)

Speaker: K. Zurek (Berkeley and CERN) 

Abstract: Searches for massive dark matter have largely focused on a mass window near the weak scale, the so-called “WIMP window".  This window is, however, becoming increasingly closed by both the LHC and the unprecedented sensitivity of direct detection experiments.  At the same time, theoretical work in recent years has shown lighter dark matter candidates in a hidden sector are theoretically well-motivated, natural and arise generically in many theories beyond the standard model.  New ideas are needed to search for dark matter with mass below a GeV and as light as the warm dark matter limit of a keV. We propose new ideas to search for such light dark matter with superconductors, semi-conductors, graphene, Dirac materials, and superfluid helium.  We show that these same experiments, through inelastic processes, may also be sensitive to dark matter with masses in the meV to keV mass window, broadening the mass reach to light dark matter by many orders of magnitude.

Slides: http://reunion.uv.es/p9ofzzoe5h8/
Video: http://reunion.uv.es/p190n0q2eyr/

Neutrinos and Neutron-Star Merger, I. Tamborra

Date and time: Tuesday February 6th @ 15:00 (CET)

Speaker: I. Tamborra (Niels Bohr)
 
Abstract: The merging of two neutron stars or a neutron star and a black hole are dense in neutrinos.  We will review the role of neutrinos and their flavor conversions in the synthesis of the heavy elements above the merger torus. The chances of detecting high-energy neutrinos produced in the merger aftermath will be also discussed.
 
 

Distinguishing axions from WIMPs as CDM?, S. Davidson

Date and time: January 9th, 2018 at 15:00 (CET)
Speaker: S. Davidson (CNRS)
Abstract: The QCD Axion is a Beyond-the-standard-model Curiosity. Originally introduced to solve the strong CP problem, it is effectively described by  a one-particle, one-parameter new physics model,  and, despite having a mass comparable to the neutrino's, it is a Cold Dark Matter candidate. In the scenario where the axion is born after inflation, I will review the growth of Large Scale Structure in the presence of axion CDM, and speculate about  axion configurations in our galaxy today.
 

QCD and Baryogenesis

Time and date:  Tuesday December 10th   @15:00 (CET)

Speaker: Seyda Ipek (Department of Physics and Astronomy, University of California Irvine)

Abstract:  Generally we do not think about QCD when we try to explain the matter--antimatter asymmetry of the universe. I will describe a small modification to the SM which drastically changes the QCD confinement in the early universe. In this model the strong coupling constant is a dynamical quantity which depends on the vacuum expectation value of a new scalar field. In this history of our Universe the QCD confines through a first-order phase transition at a temperature of T ~ O(100 GeV), when sphalerons are still active. Large CP violation can also exist in the strong sector — which is then cancelled by the QCD axion. I will explain this baryogenesis scenario and the rich set of phase transitions in the model.

Slides: http://reunion.uv.es/p24kd3ehuum/

Video:  http://reunion.uv.es/p2zrbqigyg1/

Heavy sterile neutrino emission in core-collapse supernovae: constraints and signatures

Time and date:  Tuesday November 26th @15:00 (CET)

Speaker: Leonardo Mastrototaro (Interuniversity department of physics “Michelangelo Merlin”)

Abstract:  Heavy sterile neutrinos with masses in the MeV-GeV are predicted in extension of the Standard Model, like neutrino Minimal Standard Model (νMSM). In this talk, we consider the possibility that heavy sterile neutrinos with masses O(100) MeV are produced in the core of a collapsing supernova (SN). We will constrain the mass-mixing parameter space of the heavy sterile neutrino, from the energy loss argument from SN 1987A. Finally, we will characterize the observable active neutrino signal in large underground detectors, induced by decays of heavy sterile neutrinos in the SN envelope.

This talk is based on: Leonardo Mastrototaro, Alessandro Mirizzi, Pasquale Dario Serpico and Arman Esmaili, “Heavy sterile neutrino emission in core-collapse su- pernovae: Constraints and signatures” (2019), arXiV:1910.10249

Slides:   http://reunion.uv.es/p644jiwal03/

Video:   http://reunion.uv.es/p50s2tudgky/

 

Exploring the Dark Matter ALPs

Time and date:  Tuesday November 12th @15:00 (CET)

Speaker: Joerg Jaeckel (Institut für Theoretische Physik, Universität Heidelberg)

Abstract: In this talk we will have a look at dark matter made from very light bosons. After a brief review of the standard scenario of axion-like particles (ALPs) we will discuss some surpising aspects regarding the stability of ALP DM. Then we turn to non-minimal models. In particular we consider a scenario where the field space of the ALP is enlarged by a monodromy. In addition we have a look at the case where the light boson caries an approximately conserved charge.

Slides:   http://reunion.uv.es/p1bhyt8xygr/

Video:   http://reunion.uv.es/p5loz1xl5nc/

Dark and shiny dresses around primordial black holes

Time and date:  May 28, 2019 at 15h00 CET

Speaker: Daniele Gaggero (Instituto de Física Teórica UAM/CSIC)

Abstract: The birth of gravitational wave astronomy has been a major recent breakthrough in physics. The recent discovery of gravitational wave signals from merger events of massive binary-black-hole (BBH) systems have prompted a renewed debate in the scientific community about the existence of primordial black holes of O(1-100) solar masses. These objects may have formed in the early Universe and could constitute a significant portion of the elusive dark matter that, according to standard cosmology, makes up the majority of the matter content in the universe.

I will review the most recent development of this field, with particular focus on the mass window of interest for the LIGO and Virgo gravitational observatories. I will discuss in detail the most updated computations of the expected merger rate of a hypothetical subdominant population of primordial black holes, taking into account the impact of the dark matter “dresses” that are expected to form around these objects.

I will also present the prospects of discovery with forthcoming radio facilities such as SKA and ngVLA, and the possible consequences of such discovery on the existence of other dark matter candidates

Slides:   http://reunion.uv.es/p68do8grdom/

Video:    http://reunion.uv.es/p4dqm86vj0u/

High-Energy Neutrino Observatories Beyond the Standard Model

Time and date:  Tuesday, May 07, 2019 at 15h00 CET

Speaker: Derek B. Fox (Penn State University)

Abstract: The March 2018 report of two anomalous (Earth-emergent) e_cr ~ 0.6 EeV air showers by the ANITA collaboration has presented a severe puzzle of interpretation. Given existing limits on neutrino transient sources and the diffuse neutrino flux, these events are straightforwardly impossible under the Standard Model, due primarily to the challengesof propagating SM particles of these energies along the observed extended path lengths. I will review the nature of the ANITAexperiment and the properties of their anomalous events, and presentour arguments for the incompatibility of these observations with the Standard Model. I will also explore the possible existence of analog events among the highest-energy neutrinos of the IceCube neutrinoobservatory. Together, these observations encourage us to consider the chief alternative, that the ANITA Anomalous Events are mediated by arelatively long-lived Beyond Standard Model (BSM) particle. I will present our inferences as to the necessary properties of thisparticle, which appear consistent (at least in part) with those predicted for the "stau" slepton in some supersymmetric modelsof the fundamental interactions. LHC Run 2 data now under analysis may prove to be highly relevant in this context.

Slides:    http://reunion.uv.es/p2gyzutssmz/

Video:    http://reunion.uv.es/p94ldyw1rj8/

Linking lepton number violation with B anomalies

Time and date:  April 23, 2019 at 15h00 CET

Speaker: Thomas Mannel and Oscar Catà (Siegen University)

Abstract: Hints of violation of lepton flavor universality in semileptonic B decays have prompted a renewed interest in leptoquarks at the low TeV scale. Among the different scenarios suggested, some happen to violate also lepton number, yet not much attention has been paid to the expected size of the associated lepton number violating processes. In this webinar we will consider this issue, starting from a short introduction into the status of  the B anomalies. We write down a model in terms of two leptoquarks which has a softly broken lepton number and discuss its predictions for neutrino masses and lepton-number violating B decays. 

Slides:    http://reunion.uv.es/p5d6pl9u6oq/

Video:   http://reunion.uv.es/p4ip9qiaviu/

How to relax the cosmological neutrino mass bound

Time and date:  April 9th at 15h00 CET

Speaker: Isabel M. Oldengott (IFIC UV-CSIC)

Abstract: The by far strongest bound on the sum of the neutrino masses today comes from cosmological observations. Future surveys promise to even tighten this bound significantly and will be realized within the next decade. It is therefore crucial to be aware of parameter degeneracies and the main assumptions hiding behind the cosmological mass bound. We study the impact of non-standard momentum distributions of cosmic neutrinos on the anisotropy spectrum of the cosmic microwave background and the matter power spectrum of the large scale structure.

We show that the neutrino distribution has almost no unique observable imprint, as it is almost entirely degenerate with the the neutrino mass and the effective number of neutrino flavours. Performing a Markov chain Monte Carlo analysis with current cosmological data, we demonstrate that the neutrino mass bound therefore heavily depends on the assumed momentum distribution of relic neutrinos.

Slides:   http://reunion.uv.es/p725larw5k1/

Video:  http://reunion.uv.es/p25zeng2bc8/

The Neutrino Puzzle: Anomalies, Interactions, and Cosmological Tensions

Time and date:  Tuesday March 26th at 15h00 CET

Speaker: Francis-Yan Cyr-Racine (University of Harvard)

Abstract: New physics in the neutrino sector might be necessary to address anomalies between different neutrino oscillation experiments. Intriguingly, it also offers a possible solution to the discrepant cosmological measurements of H_0. We show here that delaying the onset of neutrino free-streaming until close to the epoch of matter-radiation equality can naturally accommodate a larger value for the Hubble constant, while not degrading the fit to the cosmic microwave background (CMB) damping tail.

We achieve this by introducing neutrino self-interactions in the presence of a non-vanishing sum of neutrino masses. This "strongly interacting" neutrino cosmology prefers a 3+1 neutrino scenario, which has interesting implications for particle model-building and neutrino oscillation anomalies. Due to their impact on the evolution of the gravitational potential at early times, self-interacting neutrinos and their subsequent decoupling leave a tell-tale structure on the matter power spectrum. Our analysis shows that it is possible to find radically different cosmological models that nonetheless provide excellent fits to the data, hence providing an impetus to thoroughly explore alternate cosmological scenarios.

Slides:  http://reunion.uv.es/p2yca55dgs2/

Video: http://reunion.uv.es/p2kvd6mhkd0/

New results on the sub-GeV Dark Matter Frontier

Time and date:  Tuesday March 12th at 15:00 CET

Speaker: Tien-Tien Yu (University of Oregon)

Abstract: The sub-GeV dark matter mass range has received increased interest in the last several years, owing to the lack of any unambiguous signal of the canonical WIMP in the GeV-TeV mass range. The sub-GeV mass range is relatively unexplored due to the difficulty of detecting such light dark matter with traditional techniques. However, there have been recent experimental developments that finally make sub-GeV direct detection viable.

I will discuss some of the theoretical principles and strategies to explore sub-GeV dark matter candidates, as well as some current and proposed experimental techniques. I will focus predominantly on semiconductor targets, such as the new SENSEI experiment which utilizes silicon CCDs, and demonstrate the potential for exploring the eV-GeV dark matter mass range in the near future.

Slides:  http://reunion.uv.es/p2vuydwydjy/

Video:  http://reunion.uv.es/p1y6nzluhia/

Dark Neutrino and Explanation of MiniBooNE Anomaly Under Siege

Time and date:  Tuesday February 12th, 2019

Speaker: Carlos Argüelles Delgado (Massachusetts Institute of Technology)

Abstract: Recently it has been suggested that the MiniBooNE excess can be explain by introducing a dark sector that which comprises of a dark neutrino and photon. These types of models are naturally embedded in neutrino mass generation scenarios. In this talk, we use neutrino scattering data from Minerva and CHARM-II to probe this class of models. We argue that by using sideband measurements of neutrino-electron scattering, we can significantly explore the parameter space motivated by the MiniBooNE results. Our new constraints show that a simultaneous explanation of the angular and energy distributions of the excess is in tension with neutrino-electron scattering data. Finally, we discuss how these types of measurements can play a role in further constraining the parameter space of these models.

Slides: http://reunion.uv.es/p4pshlsgzv8/

Video: http://reunion.uv.es/p8on58zby2e/

 

"New Directions for Thermal Dark Matter"

Time and date: Tuesday, July 7th, 2020 @15:00 (CET)

Speaker: Juri Smirnov (Ohio State U.)

Title: "New Directions for Thermal Dark Matter"

Abstract: Thermal production mechanisms are a highly predictive framework in the dark matter model space. Charting possible realizations is important, as it leads to insights that guide experimental efforts to fully test particle dark matter. I will discuss bound-state formation effects that can affect the thermal relic abundance and lead to new dark matter scenarios and signatures. I will also present a novel thermal dark matter production mechanism, that can lead to monoenergetic electron recoils in laboratory experiments, for example XENON1T.

Slides: files/New_Directions_Thermal_DM_HiDDeN-.pdf

Video: https://eu-lti.bbcollab.com/recording/0fd5f89369294e708319b6c3c9d467f1

"Unravelling richness of dark sector by FASER$\nu$"

Time and date: Tuesday, June 16th @15:00 (CET)

Speaker: Yasaman Farzan (IPM, Iran & ICTP, Italy)

Title: "Unravelling  richness of dark sector by FASER$\nu$"

Abstract: FASER$\nu$ is a newly proposed experiment which will take data in  run III of the LHC during 2021-2023. It will be located in front of the FASER detector, 480~m away from the ATLAS interaction point  in the forward direction. Its main goal is to detect neutrinos of all flavors produced at the interaction point with superb precision in reconstructing charged tracks. This capability makes FASER$\nu$ an ideal setup for uncovering the pattern and properties of a light dark sector. We demonstrate this capability for a well-motivated class of  models with a dark matter candidate of mass around a few GeV. Dark matter annihilates to a pair of intermediate neutral particles that subsequently decay into the standard model charged fermions. We show how FASER$\nu$ can shed light on the structure of the dark sector by unravelling the decay chain within such models.

Slides: files/yasaman_slides.pdf

Video: https://eu-lti.bbcollab.com/recording/2d50f73fd46941c8a0989e935e74969a

 

 

 

Detecting (Axion?) Dark Matter around Black Holes with Gravitational Waves

Time and date:  Tuesday April 21  @15:00 (CET)

Speaker:  Bradley Kavanagh (IFCA, Santander)

Title: "Detecting (Axion?) Dark Matter around Black Holes with Gravitational Waves"

Abstract: The observation of Gravitational Waves (GWs) has opened up a whole new avenue for constraining and detecting particle Dark Matter (DM). One of the most promising systems to study is the Intermediate Mass Ratio Inspiral (IMRI): a stellar-mass compact object such as a neutron star inspiraling towards an intermediate mass black hole, thousands of times more massive than the Sun. Sub-hertz GWs emitted during the inspiral should be detectable by future space-based observatories such as LISA. But the presence of DM in the system can have subtle dynamical effects on the inspiral, altering the waveform and hopefully allowing us to map out the DM distribution. In addition, multimessenger signals can arise when the DM is in the form of QCD axions, in which case the strong magnetic fields around the neutron star allow the conversion of axions to radio photons. Joint observations in GWs and radio would thus provide not only a detection of Dark Matter, but also a striking confirmation of its particle nature.

Slides:: http://bradkav.net/assets/slides/KAVANAGH-HiddenNetwork2020.pdf

Video:  https://eu-lti.bbcollab.com/recording/295c7e48035b48f39bf5d4dc2c1647eb

 

Millicharged particles in neutrino detectors

Time and date: Tuesday May 5th  @15:00 (CET)

Speaker:  Ryan Plestid (Kentucky U. & Fermilab)

Title: "Millicharged particles in neutrino detectors"

Abstract:  Millicharged particles (mCPs) represent one of the most minimal extensions of the Standard Model, and, until recently, were surprisingly poorly constrained for masses greater than roughly ~100 MeV. Recent proposals to discover mCPs have focussed on intense proton beams which result in meson cascades that can provide extremely large fluxes of mCPs; this "beam" of mCPs can, in turn, be detected at downstream detectors. 
In this talk I will discuss how cosmic rays can act as a proton beam in their own right with the upper atmosphere serving as a fixed (and very thick) target. I will explain how, by combining well understood meson production cross sections, one can calculate the flux of mCPs from primary pp collisions. We find competitive constraints with accelerator based experiments, and find that our results can limit a recently proposed strongly-interacting dark matter "window".

Slides: https://drive.google.com/file/d/1zi4m-7Wou_3D1fvYxXH2sbIwbf1353Aw/view

Video: https://eu-lti.bbcollab.com/recording/f5033741c37345d281511731a5ebf95f

 

Searching for dark sectors with Kaon factories

Time and date: Tuesday May 19th  @15:00 (CET)

Speaker: Gilad Perez (Weizmann Institute of Science)

Title: "Searching for dark sectors with Kaon factories"

Abstract: The two kaon factories, KOTO and NA62, are at the cutting edge of the intensity frontier, with an unprecedented numbers of long lived and charged Kaons, ~ 10^{13}, being measured and analyzed. These experiments have currently a unique opportunity to search for dark sectors. We demonstrate, both via studying the experimental property and by constructing new physics (NP) models, that the searches done at KOTO and NA62 are complementary, both probing uncharted territories. We also mention that the model may be compatible with the preliminary analysis of the KOTO-data that shows a hint for NP.

Slides: Clik here

Video: https://eu-lti.bbcollab.com/recording/9ff577b36bd1456184f28a4ec636717f

 

 

 

A little theory of everything

Time and date:  Tuesday March 24 @15:00 (CET)

Speaker:  James Cline (McGill University)

Abstract: I present a minimal model that attempts to address the main missing ingredients of the standard model: inflation, baryogenesis, dark matter, and the origin of neutrino masses.  We introduce a complex inflaton that decays into three generations of GeV-scale heavy neutral leptons, creating a lepton asymmetry during inflation.  One HNL is stable and provides (partially) asymmetric dark matter.  A light scalar singlet is needed to suppress its symmetric relic density.  Neutrino masses are generated by the usual seesaw mechanism, with heavy right-handed neutrinos above the inflation scale, and an MFV-like ansatz that relates neutrino masses to the HNL couplings, that are then linked to the light neutrino properties with only one adjustable parameter.  The stability of dark matter implies the lightest neutrino is massless.  The model is highly testable, and could explain excess events recently seen by KOTO.

Slides: Click here

Video: https://cloud.ift.uam-csic.es/s/BEiiYSLmjnJQcBQ

Dark Matter Halos from Parametric Resonance and their Signatures

Time and date:  Tuesday March 10th @15:00 (CET)

Speaker: Asimina Arvanitaki (Perimeter Institute for Theoretical Physics)

Abstract: While there is undisputed evidence for Dark Matter, its nature and properties remain one of the biggest questions of our time. What is Dark Matter(DM)? How is it produced? Does it have interactions other than gravitational? In this talk, I will describe how a large class of bosonic particles can account for the DM of the Cosmos. These particles can be much lighter than those of the Standard Model with Compton wavelengths that are bigger than the size of our solar system or smaller than a millimeter. In the presence of attractive self-interactions, there is a parametric resonance effect in the early universe that can cause growth of structure at small scales, an effect so dramatic that can cause structures to collapse well before matter-radiation equality. The signatures of this effect span several experiments and orders of magntude in parameter space. When the DM boson is heavy, the dense DM halos can alter the optimal search strategies in direct detection experiments. When the DM boson is light, these halos may leave their imprint in searches for dark matter substructure, primordial gravitational waves and alter the star formation history of the universe.

Slides: Click here

Video:  https://eu-lti.bbcollab.com/recording/da6353bcb530475cb90308dbd36911d5

Long-lived particle search @ LHC

Time and date:  Tuesday February 25th @15:00 (CET)

Speaker:  Xiao- Ping Wang (HEP Argonne National Lab)

Abstract:  Long-lived particle is well motivated for the new physics search both for collider phenomenology and dark sector. We make use of new variables related to position to search for long-lived, basing on current CMS detector and the Phase-2 Upgrade of the CMS endcap calorimeter which is a high granularity silicon-based calorimeter (HGCAL). We study the long-lived particle signal induced by long-lived sterile neutrino and long-lived Higgs portal particle. The position related variables have been developed to suppress QCD and fake track backgrounds. The final results depends on trigger performance and are generally promising.

Slides: Click here

Video:  https://eu-lti.bbcollab.com/recording/b315995f75c94354b9a8477dc17abb58

Neutrino masses from gravity

Time and date:  Tuesday February 11th @15:00 (CET)

Speaker: Jessica M. Turner (Fermilab)

Abstract:  In this talk I will discuss neutrino masses in general and demonstrate that non-zero neutrino masses can be generated from gravitational interactions. In this work we  solve the Schwinger-Dyson equations to find a non-trivial vacuum thereby determining the scale of the neutrino condensate and the number of new particle degrees of freedom required for gravitationally induced dynamical chiral symmetry breaking. We show for minimal beyond the Standard Model particle content, the scale of the condensation occurs close to the Planck scale.

Slides: Click here

Video:  https://eu-lti.bbcollab.com/recording/c2c49468eb6d4fc8af8a00309496b387

Probing the Neutrino Mass Mechanism with the CMB

Time and date:  Tuesday January 28th @15:00 (CET)

Speaker: Samuel J. Witte (Instituto de Física Corpuscular, UV/CSIC)

Abstract:  I will present recent work investigating the extent to which the CMB can serve as an indirect probe of neutrino mass models that contain a light neutrino-philic goldstone boson (or bosons). As a specific example I will focus the case where the type-I seesaw mechanism is realized from the spontaneous breaking of a global B-L symmetry, the pseudo goldstone boson here being identified as the majoron. I will show that current observations by Planck allow one to constrain symmetry breaking scales as high as ~ 1 TeV for majoron masses near the ~ eV scale. I will then discuss the current status of the so-called Hubble tension, and show that the present of a light majoron can help ameliorate this outstanding discrepancy.

Slides: Click here

Video:  https://eu-lti.bbcollab.com/recording/e113ad0be20e4c9daa9fb8da1ff39888

Filtered Dark Matter: Setting the Dark Matter Abundance Through a First Order Phase Transition

Time and date:  Tuesday January 14th @15:00 (CET)

Speaker: Joachim Kopp (CERN & Mainz Institute for Theoretical Physics & PRISMA Cluster of Excellence)

Abstract:  We discuss the critical role that first order phase transitions in the early Universe may play in the production of dark matter.  We describe a mechanism dubbed "Filtered Dark Matter", where it is assumed that dark matter particles acquire mass during the phase transition, making it energetically unfavourable for them to enter the expanding bubbles of the massive phase. Instead, most of them are reflected off the advancing bubble walls and quickly annihilate away in the massless phase. Only the dark matter particles which have entered the bubbles survive to constitute the observed dark matter today.  Towards the end of the talk, we will also briefly mention other ways in which phase transitions can be crucial in determining the dark matter abundance, and we discuss how such scenarios can be probed experimentally.

Slides: Click here

Video:  https://eu-lti.bbcollab.com/recording/3828066bab8246b2b2bb107c2c32b66a

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