College of Science Physics Dept Talks 
Center for Neutrino Physics 
Center for Neutrino Physics Seminars Fall 2016  Spring 2017 [ Aug  Sept  Oct  Nov  Dec  Jan  Feb  Mar  Apr  May ] Coordinators: Lara Anderson, Shunsaku Horiuchi, Tommy O'Donnell 
20152016 
20172018 
August 2016  
2:30pm  3:30pm 304 Robeson Special Day and Time 
Neil David Barrie
(University of Sydney) Cosmological Implications of Anomalies The presence of anomalies in theories can lead to interesting cosmological phenomena through the ChernSimons terms to which they relate. The possible implications for Baryogenesis/Cogenesis and Gravitational waves shall be explored. Firstly, we propose a new mechanism for generating both luminous and dark matter during cosmic inflation. According to this mechanism, ordinary and dark matter carry common charge which is associated with an anomalous U(1)X group. Anomaly terms source CP and U(1)X charge violating processes during inflation, producing corresponding nonzero ChernSimons numbers which are subsequently reprocessed into baryon and dark matter densities. The general framework developed is then applied to two possible extensions of the Standard Model with anomalous gauged B and BL, each with an additional dark matter candidate. Secondly, we investigate the propagation of gravitational waves through the cosmic neutrino background, assuming it carries a nonzero lepton asymmetry. In this background, the graviton dispersion relation is found to exhibit birefringent behaviour, analogous to ChernSimons modified gravity, leading to an enhancement/suppression of the gravitational wave amplitudes depending on the polarisation, where the magnitude of this effect is related to the size of the lepton asymmetry. The heralding of the new era of gravitational wave astronomy may allow the investigation of this behaviour and provide an indirect way to learn about the properties of the cosmic neutrino background and the neutrino sector.Host: Tatsu Takeuchi 
4:00pm  5:00pm 304 Robeson 
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September 2016  
2:30pm  3:30pm 304 Robeson (Poster) Special Time 
Peter Koroteev
(Perimeter Institute) Instanton Counting in LargeN Gauge Theories We study supersymmetric gauge theories with eight supercharges with large number of colors. We show that the instanton counting initially proposed by Nekrasov has a different realization in therm of the effective largeN theory. This observation suggests a network of dualities between gauge theories, topological strings and integrable systems. As a part of a bigger picture we explore the correspondence between three branches of mathematics and physics: geometric representation theory, integrable systems and supersymmetric gauge theories and string/M theory. In the example which I will illustrate we find intricate connections between representations of algebras (like double affine Hecke algebra, Ding Iohara algebra), quantization of integrable manybody systems (like CalogeroMoser, RuijsenaarsSchneider, spin chains) and instanton (vortex) counting of supersymmetric gauge theories of SeibergWitten type. Our results give rise to some new mathematebical conjectures.Host: Lara Anderson 
2:30pm  3:30pm 210 Robeson Special Day, Time, and Place 
Michael Wilking
(Stony Brook) The Difficult Search for CP Violation in Neutrinos Over the past 2 decades, neutrino physics has progressed from the initial discovery of neutrino oscillations to the precise knowledge of all three angles in the PMNS neutrino mixing matrix. We may now be on the verge of discovering the last piece of the neutrino mixing puzzle: leptonic CP violation. To observe CP violation, experiments must make precise, differential measurements of the appearance of electron neutrinos and antielectron neutrinos. This requires unprecedented control of systematic uncertainties, and, in particular, an understanding of neutrinonucleus interactions that is beyond the capabilities of existing theoretical models. The resulting "neutrino energy measurement problem" will be discussed, as well as a potential experimental solution to this problem, the NuPRISM detector, which is being planned for installation at the Japan Proton Accelerator Research Complex (JPARC).Host: Camillo Mariani 
4:00pm  5:00pm 304 Robeson (Poster) 
Rohana Wijewardhana
(University of Cincinnati) Collapse of Axion Stars Axion stars, gravitationally bound states of lowenergy axions, described by a field theory with potential energy $f^2 m^2(1Cos (A/f))$ have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as a result, they are well described by a leadingorder expansion of the axion potential. Heavier states are susceptible to gravitational collapse. Inclusion of higherorder interactions, present in the full potential, can give qualitatively different results in the analysis of collapsing heavy states, as compared to the leadingorder expansion. In this work, we find that collapsing axion stars are stabilized by repulsive interactions present in the full potential, providing evidence that such objects do not form black holes. These dense configurations, which are the endpoints of collapse, have extremely high binding energy, and as a result, quickly decay through number changing interactions. Host: Tatsu Takeuchi 
4:00pm  5:00pm 304 Robeson 
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October 2016  
4:00pm  5:00pm 304 Robeson (Poster) Special Day 
Tristan Hubsch
(Howard University) Evidence for nonConvex Mirror Manifolds While being the prime candidate by far in providing the framework for a "theory of everything," superstring theory also requires hiding 60% of spacetime. Finding out ways of doing so has spurred a competition between physics and mathematics that continues to deliver surprises on both fronts. The recent realization by the VTech research group that such hidden spacetime dimensions may well be described using Laurent defining equations has inspired a rethinking of socalled toric geometry that describes the ground states in Witten's gauged linear sigma model (GLSM)  the underlying worldsheet field theory. Starting with an adaptation of GLSM, I will describe the corresponding adaptation of toric geometry, discovering that a by now quartacentenarian construction of mirror manifolds thrives within these nonconvex polytopes Host: Lara Anderson 
10:00am  11:00am 216 Randolph (Poster) Special Day, Time, and Place 
Jim Halverson
(Northeastern University) String Theory and the Dark Glueball Problem String compactifications, and perhaps more general UV complete theories, give rise to fourdimensional effective theories with many degrees of freedom. These may be produced in the early universe, leading to cosmologically interesting or fatal features depending on the case. In this talk I'll discuss the case of populating pure YangMills sectors by inflation or modulus decay, which give rise to dark glueballs as the universe cools. These are terrible dark matter candidates, frequently overproducing dark matter or spoiling nucleosynthesis. We will argue that the problem is severe in string theory, where many such sectors are common, and motivate models of asymmetric reheating as a potential solution. Host: Lara Anderson 
2:30pm  3:30pm 304 Robeson (Poster) Special Time 
Hee Cheol Kim
(Harvard University) Monopoles and Vortices in 3d N=4 gauge theories In 3d gauge theories, monopole operators create and destroy vortices. The monopole operators generate an interesting algebra which naturally acts on vortex states. In this talk, I will show how to construct these 3d monopole operators in the 1d quantum mechanics describing the moduli space of vortices and also show that the quantum algebra generated by monopole operators can be obtained from localization computation.Host: Lara Anderson 
4:00pm  5:00pm 304 Robeson (Poster) 
Markus Ahlers
(University of WisconsinMadison) MultiMessenger Aspects of Cosmic Neutrinos The recent observation of TeVPeV neutrinos by IceCube has opened a new window to the highenergy Universe. These highenergy astrophysical neutrinos are expected to originate from cosmicray interactions with gas and radiation. The origin of the IceCube signal is presently unknown and various Galactic and extragalactic source candidates have been proposed. Multimessenger studies can help to decipher the underlying mechanisms of particle acceleration, propagation and production. I will highlight in my talk various source scenarios and will discuss multimessenger constraints from cosmicray and gammaray observations. Host: Shunsaku Horiuchi 
4:00pm  5:00pm 304 Robeson 
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November 2016  
4:00pm  5:00pm 304 Robeson 
Host: 
4:00pm  5:00pm 304 Robeson (Poster) 
Vedran Brdar
(U. Mainz) New physics in Supernovae and IceCube Dark matter (DM) particles can be captured by stars via scattering on ordinary matter. As a benchmark model for swave and pwave annihilation, we consider DM annihilation into dark photons and dark scalars, respectively. We trace DM capture and annihilation rates throughout the life of a massive star and show that this evolution ends in an observable gamma ray flash. In the remainder of the talk, I will discuss flavor ratios in IceCube in the 4flavor scenario assuming the presence of eV sterile neutrino.Host: Patrick Huber 
4:00pm  5:00pm 304 Robeson (Poster) 
Justin Khoury
(University of Pennsylvania) New Approaches to Dark Matter In this talk I will discuss a novel theory of superfluid dark matter. The scenario matches the predictions of the LambdaColdDarkMatter (LambdaCDM) model on cosmological scales while simultaneously reproducing the MOdified Newtonian Dynamics (MOND) empirical success on galactic scales. The dark matter and MOND components have a common origin, as different phases of a single underlying substance. This is achieved through the rich and wellstudied physics of superfluidity. The framework naturally distinguishes between galaxies (where MOND is successful) and galaxy clusters (where MOND is not): due to the higher velocity dispersion in clusters, and correspondingly higher temperature, the dark matter in clusters is either in a mixture of superfluid and normal phases, or fully in the normal phase. The model makes various observational predictions that distinguishes it from both LambdaCDM and standard MOND. In the last part of the talk, I will discuss an ongoing attempt at explaining cosmic acceleration as yet another manifestation of dark matter superfluidity. Host: Djordje Minic 
4:00pm  5:00pm 304 Robeson 
THANKSGIVING BREAK

4:00pm  5:00pm 304 Robeson (Poster) Special Day 
Barton Zwiebach
(MIT) L∞ algebra of perturbative field theory The homotopy Lie algebra L∞ is an extension of Lie algebras in which the Jacobi identity for the bracket fails, but the violation can be expressed in terms of an infinite set of higher brackets. I will give an introduction to this algebra and its axioms. Then I will provide evidence that perturbative field theories provide realizations of this algebra with irreducible with npoint functions describing structure constants of the algebra.Host: Lara Anderson 
4:00pm  5:00pm 304 Robeson (Poster) 
Shreyashi Chakdar
(UVa) Searching for Seesaw signatures at the Large Hadron Collider Observation of nonzero neutrino masses at a scale ~101 102 eV is a major problem in otherwise highly successful Standard Model. The most elegant mechanism to explain such tiny neutrino masses is the seesaw mechanism with right handed neutrinos. However, the required seesaw scale is so high (1014 GeV), it will not have any direct collider implications. Recently, in our explicit model the seesaw mechanism with the right handed neutrinos at the electroweak scale has been investigated. The model has a mirror symmetry having both the left and right lepton and quark doublets and singlets for the same SU(2)W gauge symmetry. Additional Higgs multiplets have been introduced to satisfy the precision electroweak tests, and other low energy observables. Because the scale of the symmetry breaking is electroweak, both the mirror quarks and mirror leptons have masses in the electroweak scale in the range 150  800 GeV. The mirror quarks / leptons decay to ordinary quarks /leptons plus almost massless neutral scalars. We calculate the final state signals arising from the pair productions of these mirror quarks and their subsequent decays. We find that these signals are well observable over the Standard Model background for 13 TeV LHC. Depending on the associated Yukawa couplings, these decays can also give rise to displaced vertices with long decay length (very different from the usual displaced vertices associated with b decays), which will be the distinguished signatures for this model.Host: Tatsu Takeuchi 
December 2016  
4:00pm  5:00pm 304 Robeson 
Host: 
4:00pm  5:00pm 304 Robeson 
Final Exam Week

4:00pm  5:00pm 304 Robeson 
Winter Break

4:00pm  5:00pm 304 Robeson 
Winter Break

January 2017  
4:00pm  5:00pm 304 Robeson 
Winter Break

4:00pm  5:00pm 304 Robeson 
Winter Break

4:00pm  5:00pm 304 Robeson (Poster) 
Warren Wright
(NCSU) Neutrinos from Type Ia Supernovae, DDT vs. GCD Despite their use as cosmological distance indicators and their importance in the chemical evolution of Galaxies, the unequivocal identification of the progenitor systems and explosion mechanism of normal Type Ia supernovae (SNe Ia) remains elusive. The leading hypothesis is that such a supernova is a thermonuclear explosion of a carbonoxygen white dwarf but the exact explosion mechanism is still a matter of debate. Observation of a Galactic SN Ia would be of immense value in answering the many open questions related to these events. One potentially useful source of information about the explosion mechanism and progenitor is the neutrino signal. In this presentation, I will describe our computation of the expected neutrino signal from two different explosion mechanisms and show how the flux at Earth contains features in time and energy unique to each mechanism. Then I will show the expected event rates in the SuperK, HyperK, JUNO, DUNE, and IceCube detectors. The detectable neutrino signal from each explosion mechanism is compared to reveal that the overall event rate is the most discriminating feature between the two scenarios followed by the event rate time structure.Host: JJ Cherry / Shunsaku Horiuchi 
4:00pm  5:00pm 304 Robeson 
Host: 
February 2017  
4:00pm  5:00pm 304 Robeson 
Host: 
4:00pm  5:00pm 304 Robeson (Poster) 
Pedro Machado
(Fermilab) Neutrino physics in dark matter experiments The next generation of dark matter direct detection experiments will be sensitive to the scattering of solar neutrinos in electrons and nuclei, a background to dark matter searches known as "neutrino floor." We investigate how this exceptional sensitivity can be used to study solar neutrino fluxes, weak mixing angle and solar observables, as well as to constrain new physics in the neutrino sector.Host: Patrick Huber 
4:00pm  5:00pm 304 Robeson (Poster) 
Lauren Hsu
(Fermi Lab) Next Generation Dark Matter Searches with SuperCDMS There is an overwhelming body of astrophysical data that confirms the existence of dark matter. This makes direct searches for dark matter one of the most promising ways to discover new particles and fields. However, the discovery of the Higgs coupled with the lack of any confirmed new physics beyond the Standard Model, has made it increasingly important to explore all regions of parameter space in the search for dark matter. Thus the SuperCDMS collaboration is now focusing on the search for low mass WIMPs and other light dark matter particles. A "nextgeneration" experiment, to be built at SNOLAB, will push sensitivity to these particles many orders of magnitude below presentday limits. This will be achieved with a mixed payload of germanium and silicon detectors and with two designs, the iZIP and the HV detector. I will describe the concept for the SuperCDMS SNOLAB experiment, discuss the sensitivity to dark matter, and present the current status and progress towards construction. Time permitting, I will discuss the implications of understanding the energy scale for the experiment and why this calibration is critical to its success.Host: T. O'Donnell 
4:00pm  5:00pm 304 Robeson (Poster) 
Nick Rodd
(MIT) Gammaray Constraints on Decaying Dark Matter and Implications for IceCube Utilizing the Fermi measurement of the gammaray spectrum toward the Galactic Center, we derive some of the strongest constraints to date on the dark matter (DM) lifetime in the mass range from hundreds of MeV to above an EeV. Our profilelikelihood based analysis relies on 413 weeks of Fermi Pass 8 data from 200 MeV to 2 TeV, along with uptodate models for diffuse gammaray emission within the Milky Way. We model Galactic and extragalactic DM decay and include contributions to the DMinduced gammaray flux resulting from both primary emission and inverseCompton scattering of primary electrons and positrons. For the extragalactic flux, we also calculate the spectrum associated with cascades of highenergy gammarays scattering off of the cosmic background radiation. We argue that a decaying DM interpretation for the 10 TeV1 PeV neutrino flux observed by IceCube is disfavored by our constraints. We interpret the results in terms of individual final states and in the context of simplified scenarios such as a hiddensector glueball model.Host: Oscar Macias / Shunsaku Horiuchi 
March 2017  
4:00pm  5:00pm 304 Robeson (Poster) 
Doug Edmonds
(Emory & Henry College) Modified Dark Matter: Does Dark Matter Know about the Cosmological Constant? Modified Dark Matter (MDM) is a phenomenological model of dark matter that behaves like CDM at large scales, but naturally accounts for the universal acceleration constant observed in galactic rotation curve data. We provide a theoretical justification for the proposed MDM mass profile based on arguments of gravitational thermodynamics and show how Milgrom's scaling, usually associated with Modified Newtonian Dynamics (MOND), appears as a phenomenological manifestation of MDM. We demonstrate that MDM passes observational tests on galactic and cluster scales. Our results suggest that dark matter mass profiles contain information about the cosmological constant in a nontrivial way.Host: Djordje Minic 
4:00pm  5:00pm 304 Robeson 
Spring Break

4:00pm  5:00pm 304 Robeson (Poster) 
Postponed to May 3rd due to travel interuption
Host: 
2:30pm3:30pm 304 Robeson (Poster) Special Day 
Digesh Raut
University of Alabama (Astronomy & CNP Joint Seminar) Inflectionpoint U(1)_{X} Higgs Inflation Inflectionpoint inflation is an interesting possibility to realize a successful slowroll inflation when inflation is driven by a single scalar field with its value during inflation below the Planck mass (φ_{I} ≲ M_{Pl}). In order for a renormalization group (RG) improved effective λφ^{4} potential to develop an inflectionpoint, the running quartic coupling λ(φ) must exhibit a minimum with an almost vanishing value in its RG evolution, namely λ(φ_{I}) ≃ 0 and β_{λ}(φ_{I}) ≃ 0, where β_{λ} is the betafunction of the quartic coupling. We consider the inflectionpoint inflation in the context of the minimal U(1)_{X} extended Standard Model (SM), a generalization of the minimal U(1)_{BL} model, where the U(1)_{X} symmetry is realized as a linear combination of the SM U(1)_{Y} and the U(1)_{BL} gauge symmetries. We identify the U(1)_{X} Higgs field with the inflaton field. For a successful inflectionpoint inflation to be consistent with the current cosmological observations, the mass ratios among the U(1)_{X} gauge boson, the righthanded neutrinos, and the U(1)_{X} Higgs boson are fixed. We first consider the BL limit with the gauge boson mass less than 1 TeV. We find that the scenario can be tested in the future collider experiments such as the HighLuminosity LHC and the SHiP experiments. On the other extreme, we consider the scenario such that the U(1)_{X} gauge symmetry is mostly oriented towards the SM U(1)_{Y} direction and investigate a consistency between the inflationary predictions and the latest LHC Run2 results on the search for a narrow resonance with the dilepton final stateHost: Tatsu Takeuchi 
4:00pm  5:00pm 304 Robeson (Poster) 
Jason Detwiler
UW, Seattle Majorana Neutrinoless Double Beta Decay Experiment The Majorana Demonstrator is performing a sensitive search for the neutrinoless doublebeta decay of 76Ge using an ultralow background array of enriched HPGe detectors deployed at the Sanford Underground Research Facility in Lead, SD. This rare process is generically predicted to occur by large classes of beyondtheStandardModel theories, and its observation would indicate that lepton number is not a conserved quantity in nature, with implications for the matterdominance of the universe. The techniques used for the Majorana Demonstrator include selection and production of materials extremely low in natural radioactivity, choice of detector technology enabling active rejection of background, and graded active and passive shielding, which together give a projected background rate that is the lowest among existing techniques. First data from the Demonstrator is inhand, and I will present our preliminary background performance and sensitivity to neutrinoless doublebeta decay, as well as our recent limits on bosonic Dark Matter and other physics targets at low energy. I will discuss the current detector status and plans for future upgrades, and our ultimate goal to field a much larger array with even lower background that will be sensitive to Majorana neutrinos with an inverted mass ordering.Host: T. O'Donnell 
4:00pm  5:00pm 304 Robeson (Poster) 
Douglas Higinbotham
Jefferson Lab Applying Statistical Modeling Techniques To The Proton Radius Puzzle Recent measurements using the Lamb shift in Muonic hydrogen have determined the proton's charge radius to be 0.84 fm; while the CODATA value, which is determined from atomic hydrogen Lamb shift and electron scattering measurements, is 0.88 fm. As the proton has only one true radius, the systematic difference the radius extracted from different measurement techniques has become known as the proton radius puzzle. I will summarize the history proton radius results and I will then discuss the pure statistical methods that were recently used by groups in Virginia (JLab, UVA, and W&M) that yield an electron scattering result that is in agreement with the Muonic hydrogen Lamb shift results. I will also discuss the important distinction between linear regression and nonlinear regressions as well as the tradeoff between bias and variance.

April 2017  
4:00pm  5:00pm 304 Robeson (Poster) 
Cecilia Lunardini
(Arizona State University) High Energy Neutrinos from the Tidal Disruption of Stars A star that transits too close to a supermassive black hole is destroyed by the black hole's strong tidal forces. The star's debris are then accreted onto the black hole, thus producing a luminous flare. To date, more than 60 candidate tidal disruption events (TDE) have been observed. In the past few years, Xray observations have established that some extreme TDE produce relativistic jets, which could accelerate cosmic rays to extremely high energy. I discuss the production of high energy neutrinos in these TDEgenerated jets, and show that the diffuse flux of these neutrinos could be detectable, and could explain part of the flux observed by the IceCube neutrino detector at 0.11 PeV energy.Host: Shunsaku Horiuchi 
4:00pm  5:00pm 304 Robeson 
Host: 
4:00pm  5:00pm 304 Robeson (Poster) Special Day 
Onkar Parrikar
University of Pennsylvania Entanglement Entropy in ChernSimons Theory and Link Invariants We will study the entanglement structure of states in ChernSimons (CS) theory defined on ncopies of a torus. We will focus on states created by performing the Euclidean pathintegral of CS theory on special 3manifolds, namely link complements in S^3. The corresponding entanglement entropies provide framing independent linkinvariants. In U(1)_k CS theory, we will give a general formula for the entanglement entropy across a bipartition of a generic nlink into sublinks. In the nonAbelian case, we study various interesting 2 & 3links including the Whitehead link & Borromean rings, both of which have nontrivial entanglement structures.

4:00pm  5:00pm 304 Robeson 
Prof. Irina Mocioiu
(Pennsylvania State) TBD Host: Djordje Minic 
4:00pm  5:00pm 304 Robeson 
Daniel Siegel
Columbia University TBD (LIGO, EM and Neutrino counterparts) Host: T. O'Donnell 
May 2017  
4:00pm  5:00pm 304 Robeson (Poster) 
Kyungeun Lim
Yale University Results of DMICE17 and Prospects of the DMIce/COSINE100 Experiments The DMIce experiment aims at the direct detection of annuallymodulating WIMP (Weakly Interacting Massive Particle) dark matter signal using NaI(Tl) detectors. DMIce17, the ?rstgeneration detector with 17 kg of NaI(Tl) deployed in the South Pole ice in December 2010, demonstrated the feasibility of running the NaI(Tl) detectors in the South Pole. In 2016, DMIce and KIMS founded a joint collaboration, COSINE100, and deployed 106 kg of NaI (Tl) detectors in the Yangyang laboratory in South Korea to look for the WIMPinduced annual modulation in the Northern hemisphere ?rst. The ?rst phase datataking of COSINE100 started in the fall of 2016, with 8 NaI(Tl) crystals immersed in the ? 2000 liters of liquid scintillator. In this talk, I will present the results of DMIce17 with more than three years of data. I will also present the current status and prospects of COSINE100.Host: T. O'Donnell 
4:00pm  5:00pm 304 Robeson 
Final Exam Week
