118834481
Here be dragons: the unexplored continents of the CMSSM
A bstractThe Higgs boson mass and the abundance of dark matter constrain the CMSSM/mSUGRA supersymmetry breaking inputs. A complete map of the CMSSM that is consistent with these two measured quantities is provided. Various “continents”, consisting of non-excluded models, can be organized by their dark matter dynamics. The following mechanisms manifest: well-tempering, resonant pseudo-scalar Higgs annihilation, neutralino/stau coannihilations and neutralino/stop coannihilations. Benchmark models are chosen in order to characterize the viable regions. The expected visible signals of each are described, demonstrating a wide range of predictions for the 13 TeV LHC and a high degree of complementarity between dark matter and collider experiments. The parameter space spans a finite volume, which can be probed in its entirety with experiments currently under consideration.
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.
59031368
Illuminating the 130 GeV gamma line with continuum photons
A bstractThere is evidence for a 130 GeV γ-ray line at the Galactic Center in the Fermi Large Area Telescope data. Dark matter candidates that explain this feature should also annihilate to Standard Model particles, resulting in a continuous spectrum of photons. To study this continuum, we analyze the Fermi data down to 5 GeV, restricted to the inner 3◦ of the Galaxy. We place a strong bound on the ratio of continuum photons to monochromatic line photons that is independent of uncertainties in the dark matter density profile. The derived constraints exclude neutralino dark matter as an explanation for the line.
119159310
Asymmetric Dark Matter from a GeV Hidden Sector
Asymmetric dark matter (ADM) models relate the dark matter (DM) density to the baryon asymmetry, so that a natural mass scale for ADM is around a few GeV. In existing models of ADM, this mass scale is unexplained; here we generate this GeV scale for DM) from the weak scale via gauge kinetic mixing with a new Abelian dark force. In addition, this dark sector provides an efficient mechanism for suppressing the symmetric abundance of DM through annihilations to the dark photon. We augment this sector with a higher dimensional operator responsible for communicating the baryon asymmetry to the dark sector. Our framework also provides a DM candidate for gauge mediation models. It results in a direct detection cross section of interest for current experiments: {sigma}{sub p} < or approx. 10{sup -41} cm{sup 2} for DM masses in the range 1-15 GeV.
118984899
Singlet-Doublet Dark Matter
In light of recent data from direct detection experiments and the Large Hadron Collider, we explore models of dark matter in which an SU(2){sub L} doublet is mixed with a Standard Model singlet. We impose a thermal history. If the new particles are fermions, this model is already constrained due to null results from XENON100. We comment on remaining regions of parameter space and assess prospects for future discovery. We do the same for the model where the new particles are scalars, which at present is less constrained. Much of the remaining parameter space for both models will be probed by the next generation of direct detection experiments. For the fermion model, DeepCore may also play an important role.
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.
119236237
Chiral condensate in holographic models of QCD
Bottom-up holographic models of QCD, inspired by the anti-de Sitter space/conformal field theory correspondence, have shown a remarkable degree of phenomenological success. However, they rely on a number of bold assumptions. We investigate the reliability of one of the key assumptions, which involves matching the parameters of these models to QCD at high 4D momentum q{sup 2} and renormalization scale {mu}{sup 2}. We show that this leads to phenomenological and theoretical inconsistencies for scale-dependent quantities such as .
119263057
All you need is N: Baryon spectroscopy in two large N limits
The generalization of QCD to many colors is not unique; each distinct choice corresponds to a distinct $1/{N}_{c}$ expansion. The familiar 't Hooft ${N}_{c}\ensuremath{\rightarrow}\ensuremath{\infty}$ limit places quarks in the fundamental representation of $\mathrm{SU}({N}_{c})$, while an alternative approach places quarks in its two-index antisymmetric representation. At ${N}_{c}=3$ these two $1/{N}_{c}$ expansions coincide. We compare their predictions for certain observables in baryon spectroscopy, particularly mass combinations organized according to SU(3) flavor breaking. Each large ${N}_{c}$ limit generates an emergent spin-flavor symmetry that leads to the vanishing of particular linear combinations of baryon masses at specific orders in the expansions. Experimental evidence shows that these relations hold at the expected orders regardless of which large ${N}_{c}$ limit one uses, suggesting the validity of either limit in the study of baryons. We also consider a hybrid large ${N}_{c}$ limit in which one flavor is taken to transform in the two-index antisymmetric representation and the rest of the flavors are in the fundamental representation. While this hybrid large ${N}_{c}$ limit is theoretically attractive, we show that for a wide class of observables it faces some phenomenological difficulties.
14150289
Nucleon electric polarizability in soliton models and the role of the seagull terms
Abstract The full Hamiltonian of the soliton models contains no electric seagull terms. Here it is shown that if one restricts the fields to the collective subspace then electric seagull terms are induced in the effective Hamiltonian. These effective seagull contributions are consistent with gauge invariance. They also reproduce the leading non-analytic behavior of a large N c chiral perturbation theory calculation of the electric polarizability.
28698882
The Nucleon nucleon interaction and large N(c) QCD
The nature of the nonrelativistic nucleon-nucleon potential in the large N_c limit is discussed. In particular, we address the consistency of the meson exchange picture of nucleon interactions. It is shown that the nonrelativistic nucleon-nucleon potential extracted from the Feynmann graphs up to and including two-meson exchange diagrams satisfies the spin-flavor counting rules of Kaplan and Savage, and Kaplan and Manohar, provided the nucleon momenta is of order N_{c}^{0}. The key to this is a cancelation of the retardation effect of the box graphs against the contributions of the crossed-box diagram. The consistency requires including $\Delta$ as an intermediate state.
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...