Bulletin of the American Physical Society
2015 Annual Fall Meeting of the APS Prairie Section
Thursday–Saturday, November 19–21, 2015; South Bend, Indiana
Session F2: High Energy Physics |
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Chair: Adam Martin, University of Notre Dame Room: Nieuwland Science 123 |
Saturday, November 21, 2015 10:30AM - 11:06AM |
F2.00001: Neutrino Physics Invited Speaker: Andre de Gouvea I will briefly review the current status of our understanding of neutrinos - experimentally and theoretically - and discuss the current outstanding questions that drive the neutrino physics program. [Preview Abstract] |
Saturday, November 21, 2015 11:06AM - 11:18AM |
F2.00002: Higgs portals to pulsar collapse Fatemeh Elahi, Joseph Bramante Pulsars apparently missing from the galactic center could have been destroyed by asymmetric fermionic dark matter ($m_X = 1-100$ GeV) coupled to a light scalar ($m_{\phi}= 5-20$ MeV), which mixes with the Higgs boson. We point out that this pulsar-collapsing dark sector can resolve the core-cusp problem and will either be excluded or discovered by upcoming direct detection experiments. Another implication is a maximum pulsar age curve that increases with distance from the galactic center, with a normalization that depends on the couplings and masses of dark sector particles. Finally, we use old pulsars outside the galactic center to place bounds on asymmetric Higgs portal models. [Preview Abstract] |
Saturday, November 21, 2015 11:18AM - 11:30AM |
F2.00003: Solving the Little Hierarchy Problem with a U(1) Extension of the MSSM Rodolfo Capdevilla, Antonio Delgado, Adam Martin In the Minimal Supersymmetric Standard Model (MSSM) the Higgs mass is not a free parameter, but it is given in terms of the gauge couplings. In a reasonable limit, the tree-level mass is of the order of the Z boson mass, in clear contradiction with the experimental results. This value can be lifted by loop corrections via heavy virtual sparticles, where the largest contribution comes from stops. However, the so-called Electroweak fine-tuning also depend quadratically on the stop masses, which means that if the stops have to be very heavy in order to reproduce the Higgs mass, a "little" fine-tuning is re-introduced in the theory. One way to avoid this fine-tuning is to modify the tree-level quartic of the Higgs boson via new F or D term contributions, so that one does not have to rely on large loop corrections to obtain a viable Higgs mass. In this work we study a minimal U(1) extension to the MSSM. We study the stops sector of the model and we find that the correct Higgs mass is compatible with light stops around 700 - 800 GeV and a Z' resonance close to the 2.5 TeV bound from the run-I of the LHC, or with a little heavier stops 800 - 900 GeV if the Z' resonance is near 3.1 TeV. This region of parameter space will be quickly accessible at run-II of the LHC. [Preview Abstract] |
Saturday, November 21, 2015 11:30AM - 11:42AM |
F2.00004: Generating Functions for Effective Field Theory Operators Landon Lehman, Adam Martin The Hilbert series technique provides a robust way to calculate effective field theory operators, especially in situations where more traditional methods become computationally intractable. This technique will be explained, and recent work extending the method to include derivatives and calculate the dimension-8 operators in the Standard Model Effective Field Theory (SMEFT) will be reviewed. [Preview Abstract] |
Saturday, November 21, 2015 11:42AM - 11:54AM |
F2.00005: Dirac Triplet Extension of the MSSM Carlos Alvarado, Antonio Delgado, Adam Martin, Brian Ostdiek In this paper we explore extensions of the Minimal Supersymmetric Standard Model involving two $SU(2)_{L}$ triplet chiral superfields that share a superpotential Dirac mass yet only one of which couples to the Higgs fields. This choice is motivated by recent work using two singlet superfields with the same superpotential requirements. We find that, as in the singlet case, the Higgs mass in the triplet extension can easily be raised to 125 GeV without introducing large fine-tuning. For triplets that carry hypercharge, the regions of least fine tuning are characterized by small contributions to the $\mathcal{T}$ parameter, and light stop squarks, $m_{\tilde{t}_1} \sim 300-450$ GeV; the latter is a result of the $\tan{\beta}$ dependence of the triplet contribution to the Higgs mass. Despite such light stop masses, these models are viable provided the stop-electroweakino spectrum is sufficiently compressed. [Preview Abstract] |
Saturday, November 21, 2015 11:54AM - 12:06PM |
F2.00006: Background and Detector Response Studies With PROSPECT Prototype Detectors Pranava Teja Surukuchi PROSPECT, the Precision Reactor Oscillation and Spectrum Experiment, is a short baseline experiment to measure the reactor antineutrino spectrum from a highly-enriched $^{235}$U reactor. PROSPECT will utilize an antineutrino target composed of optically segmented $^6$Li loaded liquid scintillator cells with PMTs on each end of each cell. A two meter-long, 23 liter rectangular prototypes were deployed to study the performance of the PROSPECT unit scintillator cell as well as to make in-situ background radiation measurements at the intended PROSPECT deployment location near the High Flux Isotope Reactor at Oak Ridge National Laboratory. The light collection and pulse-shape discrimination are characterized for different reflector, PMT, and DAQ configurations using varied gamma and spontaneous fission calibration sources at several positions along the cells. This talk will focus on the measurement of backgrounds and study of PSD and light collection of these prototype cells [Preview Abstract] |
Saturday, November 21, 2015 12:06PM - 12:18PM |
F2.00007: PROSPECT: A Precision Reactor Oscillation and Spectrum Experiment Xianyi Zhang Current reactor antineutrino production models predict an antineutrino spectrum shape and normalization which are inconsistent with the existing reactor antineutrino measurements. These discrepancies could be due to the lack of understanding of the underlying nuclear physics leading to imperfect reactor antineutrino production models. Sterile neutrinos with a mass splitting of order $\Delta$m$^2 \sim$\hspace{2pt}1\hspace{2pt}eV$^2$ could also explain the disagreements. PROSPECT is a U.S.-based multi-phased reactor antineutrino experiment designed to make a precise measurement of reactor antineutrino spectrum and perform a search for sterile neutrino oscillations via electron antineutrino disappearance. PROSPECT utilizes segmented detectors with lithium-loaded liquid scintillator as the target and will be deployed at short baselines of $\sim$ 7-20 m from the High Flux Isotope Reactor, a highly-enriched uranium reactor at Oak Ridge National Laboratory. With a single year of data, PROSPECT has significant sterile neutrino discovery potential in the current global best-fit region. A suite of prototype detectors have been installed laying groundwork for deploying full-size PROSPECT detectors. This talk will focus on the PROSPECT detector design in the context of the physics goals of t [Preview Abstract] |
Saturday, November 21, 2015 12:18PM - 12:30PM |
F2.00008: The Transformation between the Sciuto, Caneschi-schwimmer-veneziano interaction vertex in the dual model and the Witten interaction vertex in split string field theory A Abdurrahman, I Abdurrahman, M Gassem In this paper we find the transformation operator between the interaction vertex in the dual model and Witten's interaction vertex in split string field theory. The procedure employed here results in an explicit conformal transformation linking the two interactions in the matter sector at all levels. Thus establishing the equivalence in the matter sector between the two theories at least at the level of the three vertex. Furthermore, we have discussed the connection between the ghost parts of the interaction vertex in both theories. The two transformations (ghost $+$ matter) differ only slightly due to the insertion of ghost number operators at the mid-point of the string for the ghost part of the vertex. The insertions are required to restore BRST invariance, which is lost when one splits the string into two parts. Also, the procedure followed here generalizes to any number of strings in a straight forward way, which is needed for a theory of closed strings. [Preview Abstract] |
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