119306471
Inert Doublet Dark Matter and Mirror/Extra Families after Xenon100
J. Stefan Institute, Ljubljana, Slovenia(Dated: May 31, 2011)It was shown recently that mirror fermions, naturally present in a number of directions for newphysics, seem to require an inert scalar doublet in order to pass the electroweak precision tests.This provides a further motivation for considering the inert doublet as a dark matter candidate.Moreover, the presence of extra families enhances the Standard Model Higgs-nucleon coupling, whichhas crucial impact on the Higgs and dark matter searches. We study the limits on the inert darkmatter mass in view of recent Xenon100 data. We nd that the mass of the inert dark mattermust lie in a very narrow window 75 1GeV while the Higgs must weigh more than 400GeV. Forthe sake of completeness we discuss the cases with fewer extra families, where the possibility ofa light Higgs boson opens up, enlarging the dark matter mass window to
118992053
Isospin-Violating Dark Matter and Neutrinos From the Sun
ux from their annihilation in the center of the Sun, in a class of theories where the dark matter-nucleon spin-independent interactions break the isospin symmetry. We point out that, while the direct detection bounds with heavy targets like Xenon are weakened and reconciled with the positive signals in DAMA and CoGeNT experiments, the indirect detection using neutrino telescopes can impose a relatively stronger constraint and brings tension to such explanation, if the annihilation is dominated by heavy quark or -lepton
30742433
Yukawa bound states of a large number of fermions
A bstractWe consider the bound state problem for a field theory that contains a Dirac fermion χ that Yukawa couples to a (light) scalar field ϕ. We are interested in bound states with a large number N of χ particles. A Fermi gas model is used to numerically determine the dependence of the radius R of these bound states on N and also the dependence of the binding energy on N. Since scalar interactions with relativistic χ’s are suppressed two regimes emerge. For modest values of N the state is composed of non-relativistic χ particles. In this regime as N increases R decreases. Eventually the core region becomes relativistic and the size of the state starts to increase as N increases. As a result, for fixed Yukawa coupling and χ mass, there is a minimum sized state that occurs roughly at the value of N where the core region first becomes relativistic. We also compute an elastic scattering form factor that can be relevant for direct detection if the dark matter is composed of such χ particles.
41782509
Direct detection of baryogenesis mechanism from squark decays at LHC
We investigate the feasibility of directly detecting a generation mechanism of the cosmic baryon asymmetry by repeating the same particle physics process inside the LHC. We propose a framework with R-parity and CP violating squark decays responsible for baryogenesis, which can be embedded in supersymmetric models and is partly motivated by naturalness. We argue that the baryon number generation here is closely related to lepton charge asymmetry on the resonance. We emphasize the importance of the single charged lepton plus multijet channel in the absence of significant missing energy in search of such a scenario.
11648919
Complementarity of LHC and EDMs for exploring Higgs CP violation
A bstractWe analyze the constraints on a CP-violating, flavor conserving, two Higgs doublet model from the measurements of Higgs properties and from the search for heavy Higgs bosons at LHC, and show that the stronger limits typically come from the heavy Higgs search channels. The limits on CP violation arising from the Higgs sector measurements are complementary to those from EDM measurements. Combining all current constraints from low energy to colliders, we set generic upper bounds on the CP violating angle which parametrizes the CP odd component in the 126 GeV Higgs boson.
44202178
Seesaw theories at LHC and warm dark matter
Explaining the origin of neutrino masses clearly requires new physics beyond the Standard Model. I focus on the Seesaw paradigm and discuss a few simplest extensions of the SM that give Majorana masses to the active neutrinos. If realized at TeV scale, seesaw theories could manifest themselves in lepton number violating signatures at both low-energy processes and high-energy collider experiments. I summarize the constraints on the seesaw scales using the current LHC data. The left-right symmetric model connects the seesaw mechanism with the origin of parity symmetry breaking, and provides a unified framework for the simplest seesaw types. With new right-handed charged-current interactions, a TeV such model offers a plethora of new particles and exotic signatures at the LHC, and also accommodates a dark matter candidate, the lightest right-handed neutrino. A challenging question is the dark matter relic density which is typically over-produced in the early universe. The late decays of two heavier right-handed neutrinos can produce entropy and dilute the dark matter number. The key observation for this picture to work is the interplay between the freeze temperature of TeV right-handed gauge interaction and the QCD phase transition. The resulting dark matter mass is predicted to be around keV which makes the left-right model also a theory of warm dark matter. I will also comment on the fate of cosmic baryon asymmetry in this scenario.
119204666
Wilson Line Response of Holographic Superconductors in Gauss-Bonnet Gravity
We study the Wilson line response in the holographic superconducting phase transitions in the Gauss-Bonnet gravity. In the black brane background case, the Little-Parks periodicity is independent of the Gauss-Bonnet parameter, while in the anti-de Sitter soliton case, there is no evidence for the Little-Parks periodicity. We further study the impact of the Gauss-Bonnet term on the holographic phase transitions quantitatively. For a given Wilson line, a bigger Gauss-Bonnet coefficient makes the phase transition easier for the black brane background while harder for the soliton background. For a given chemical potential, the response to the Wilson line is less sensitive for a bigger Gauss-Bonnet coefficient in the black brane case while the response is more sensitive in the soliton case. And more, a bigger Gauss-Bonnet coefficient makes the superconducting state more stable for both the black brane and the soliton backgrounds. DOI: 10.1103/PhysRevD.87.026002
121032641
The Virasoro algebra and group in four dimensions
The Virasoro algebra and group are examined in (3+1)‐dimensional theory with an Abelian gauge field coupled with the gravitational field. The two‐cocycle for the group is constructed by using the so‐called descent equation. Its infinitesimal version gives the Schwinger–Jackiw–Johnson term in the Virasoro algebra in 3+1 dimensions. It appears that in the case of an external monopole field the Virasoro algebra and group in 3+1 dimensions are the direct generalization of the standard ones in 1+1 dimensions, respectively.
118697431
A naturally light sterile neutrino in an asymmetric dark matter model
A bstractA recently proposed asymmetric mirror dark matter model where the mirror sector is connected with the visible one by a right-handed neutrino portal, is shown to lead naturally to a 3+1 active-sterile neutrino spectrum, if the portal consists only of two right-handed neutrinos. At tree level the model has four massless neutrino states, three (predominately) active and one sterile. The active neutrinos pick up tiny masses via the minimal radiative inverse seesaw mechanism at one-loop level. The loop effects also generate the large solar and atmospheric mixings, as well as the observed reactor mixing for certain ranges of parameters of the model. The dominant contribution to the sterile neutrino mass (~eV) arises from the gravitationally induced dimension-5 operators. Generating active-sterile mixing requires a two Higgs doublet extension of the standard model and a small mixing between the ordinary and mirror Higgs fields, which occurs naturally in mirror models.
119300744
TeV scale universal seesaw, vacuum stability and heavy Higgs
A bstractWe discuss the issue of vacuum stability of standard model by embedding it within the TeV scale left-right universal seesaw model (called SLRM in the text). This model has only two coupling parameters (λ1, λ2) in the Higgs potential and only two physical neutral Higgs bosons (h, H). We explore the range of values for (λ1, λ2) for which the light Higgs boson mass Mh = 126 GeV and the vacuum is stable for all values of the Higgs fields. Combining with the further requirement that the scalar self couplings remain perturbative till typical GUT scales of order 1016 GeV, we find (i) an upper and lower limit on the second Higgs (H) mass to be within the range: 0.4 ≤ $ \frac{{{M_H}}}{{{v_R}}} $ ≤ 0.7, where the vR is the parity breaking scale and (ii) that the heavy vector-like top, bottom and τ partner fermions (P3, N3, E3) mass have an upper bound $ {M_{{{P_3},}}}_{{{N_3},{E_3}}}\leq {v_R} $. We discuss some phenomenological aspects of the model pertaining to LHC.
14103118
Integrable electron model with correlated hopping and quantum supersymmetry
Abstract We give the q -deformed analogue of a recently introduced electron model which generalizes the Hubbard model with additional correlated hopping terms and electron pair hopping. The model contains two independent parameters and is invariant with respect to the quantum superalgebra U q ( gl (2|1)). It is shown to be integrable in one dimension by means of the quantum inverse scattering method.