118615137
Correlation between the spin-independent and spin-dependent direct detection of dark matter
We study the correlation between spin-independent and spin-dependent scattering in the context of minimal supersymmetric standard model neutralino dark matter for both thermal and nonthermal histories. We explore the generality of this relationship with reference to other models. We discuss why either fine-tuning or numerical coincidences are necessary for the correlation to break down. We derive upper bounds on spin-dependent scattering mediated by a ${Z}^{0}$ boson.
17675959
Leptophilic dark matter from the lepton asymmetry.
We present a model of weak scale dark matter (DM) where the thermal DM density is set by the lepton asymmetry due to the presence of higher dimension lepton violating operators. In these models there is generically a separation between the annihilation cross section responsible for the relic abundance (through lepton violating operators) and the annihilation cross section that is relevant for the indirect detection of DM (through lepton preserving operators). This implies a perceived boost in the annihilation cross section in the Galaxy today relative to that derived for canonical thermal freeze-out, giving a natural explanation for the observed cosmic ray electron and positron excesses, without resorting to a Sommerfeld enhancement. These models motivate continued searches for DM with apparently nonthermal annihilation cross sections. The DM may also play a role in radiatively generating Majorana neutrino masses.
118925668
Cosmic-ray induced neutrino fluxes at the Moon: A semi-analytic approach
Abstract Cosmic-ray induced neutrino backgrounds at the Moon are estimated using a semi-analytic approach. The analytic expressions are derived, flux estimates for ν e + ν ¯ e and ν μ + ν ¯ μ are given, and comparisons with the analogous backgrounds generated in the Earth’s atmosphere are presented. Suppression of the lunar fluxes relative to the terrestrial fluxes is found. At energies >10 GeV, the suppression approaches a maximum of order 10 −4 . The lower background environment suggests that the Moon may be advantageous for future particle astrophysics endeavors.
118580046
Extracting the dark matter mass from single stage cascade decays at the LHC
We explore a variant on the MT2 kinematic variable which enables dark matter mass measurements for simple, one stage, cascade decays. This will prove useful for constraining a subset of supersymmetric processes, or a class of leptophilic dark matter models at the LHC. We investigate the statistical reach of these measurements and discuss which sources of error have the largest effects. For example, we find that using only single stage cascade decays with initial state radiation, a measurement of a 150 GeV dark matter candidate can be made to $ \mathcal{O}\left( {10\% } \right) $ for a parent mass of 300 GeV with a production cross section of 100 fb and 100 fb−1 of integrated luminosity provided that backgrounds can be tightly controlled.
119221065
SUSY simplified models at 14, 33, and 100 TeV proton colliders
A bstractResults are presented for a variety of SUSY Simplified Models at the 14 TeV LHC as well as a 33 and 100 TeV proton collider. Our focus is on models whose signals are driven by colored production. We present projections of the upper limit and discovery reach in the gluino-neutralino (for both light and heavy flavor decays), squark-neutralino, and gluino-squark Simplified Model planes. Depending on the model a jets + $ E_T^{\mathrm{miss}} $, mono-jet, or same-sign di-lepton search is applied. The impact of pileup is explored. This study utilizes the Snowmass backgrounds and combined detector. Assuming 3000 fb−1 of integrated luminosity, a gluino that decays to light flavor quarks can be discovered below 2.3 TeV at the 14 TeV LHC and below 11 TeV at a 100 TeV machine.
10334629
A Comparison of Future Proton Colliders Using SUSY Simplified Models: A Snowmass Whitepaper
We present a summary of results for SUSY Simplified Model searches at future proton colliders: the 14 TeV LHC as well as a 33 TeV proton collider and a 100 TeV proton collider. Upper limits and discovery significances are provided for the gluino-neutralino (for both light and heavy flavor decays), squark-neutralino, and gluino-squark Simplified Model planes. Events are processed with the Snowmass combined detector and Standard Model backgrounds are computed using the Snowmass samples. We place emphasis on comparisons between different collider scenarios, along with the lessons learned regarding the impact of systematic errors and pileup. More details are provided in a companion paper.
122860459
Mean-field theory and solitonic matter
Abstract Finite density solitonic matter is considered in the context of quantum field theory. Mean-field theory, which provides a reasonable description for single-soliton properties gives rise to a crystalline description. A heuristic description of solitonic matter is given which shows that the low-density limit of solitonic matter (the limit which is presumably relevant for nuclear matter) does not commute with the mean-field theory limit and gives rise to a Fermi-gas description of the system. It is shown on the basis of a formal expansion of simple soliton models in terms of the coupling constant why one expects mean-field theory to fail at low densities and why the corrections to mean-field theory are nonperturbative. This heuristic description is tested against an exactly solvable 1 + 1 dimensional model (the sine-Gordon model) and found to give the correct behavior. The relevance of these results to the program of doing nuclear physics based on soliton models is discussed.
122047706
Boson mappings for schematic nuclear models with the symmetry of SO(5)
Abstract In the past, several schematic nuclear models have been proposed with the symmetry of the Lie algebra SO(5). We derive a set of mappings from the shell model spaces in which these models are defined to suitable boson spaces. The derivations are carried out by two distinct algebraic methods, which are customarily associated with the names Holstein-Primakoff and Dyson, respectively. The relative utility of the two is seen to depend on the particular mapping. The mappings are useful for the study of the collective properties of the various models and of generalizations of each of them. This is illustrated with one of the models. Some algebraic details, some ideas concerning schematic model building, and an extension of the results of this paper are presented in appendices.
118310161
Summary of Section F: QCD in Nuclear Physics and Astrophysics
This talk summarizes the Section F of “Quark Confinement and the Hadron Spectrum VII”. This section, newly added to the conference, deals with issues of QCD in nuclear physics and astrophysics.
118325367
Looking for pions in all the wrong places
In this talk, the problem of virtual pion contributions to nucleon properties is discussed. The infrared behavior of the pion propagator can lead to quantities being nonanalytic in m2π as m2π→0. It is shown that these nonanalyticities can lead to large systematic errors in the extrapolation in mq normally used in lattice QCD calculations. It is argued on the basis of both diagrammatics and large Nc QCD that quenched QCD calculation of nucleon properties includes at least some of the virtual pion effects. It is also shown that hedgehog soliton models based on large Nic QCD, have, for a certain class of observables, the same type of nonanalyticity in m2π as conventional chiral perturbation theory but with coefficients which differ by numerical constants.These constants depend only on the angular momentum and isospin of the quantity. The reason for this difference is the role of the Δ resonance which is treated differently in the two approaches. If the Δ is included realistically, one finds important correct...
118437234
Bound on the speed of sound from holography
We show that the squared speed of sound v{sub s}{sup 2} is bounded from above at high temperatures by the conformal value of 1/3 in a class of strongly coupled four-dimensional field theories, given some mild technical assumptions. This class consists of field theories that have gravity duals sourced by a single-scalar field. There are no known examples to date of field theories with gravity duals for which v{sub s}{sup 2} exceeds 1/3 in energetically favored configurations. We conjecture that v{sub s}{sup 2}=1/3 represents an upper bound for a broad class of four-dimensional theories.