118491017
Supersymmetric left–right model with radiative neutrino mass and multipartite dark matter
We propose a unified extension of the standard model with three types of coexisting dark matter, motivated by three well-studied scenarios: (1) supersymmetry with $$R$$R-parity conservation, (2) left–right symmetry where the $${SU}(2)_R$$SU(2)R doublet is not $$(\nu ,e)_R$$(ν,e)R but $$(n,e)_R$$(n,e)R where $$n$$n is a dark-matter candidate, and (3) a one-loop radiative neutrino mass model where the particles in the loop have an odd $$Z_2$$Z2 symmetry, the lightest of which is also a dark-matter candidate. Whereas there are many new particles in this model, the gauge couplings get unified in the same way as in the minimal supersymmetric standard model (MSSM). Since there are at least three dark-matter candidates, each one’s share of the total relic density of the Universe is adjustable, allowing for a much larger parameter space for the MSSM candidate itself. Our main focus is a careful study of a possible specific multipartite dark-matter scenario in this context.
123789901
Dark Matter Pions
We study the scenario where dark matter corresponds to a set of pseudoGoldstone bosons, that we call dark pions, generated by the spontaneous breaking of a symmetry in the dark sector. As a concrete example, we consider an SU(N)×SU(N) broken to the diagonal subgroup that remains an exact symmetry that ensures the stability of the dark pions, and allows a novel-interactions involving neutral gauge bosons and 3 dark pions. We study both experimental and theoretical constraints, and show that the model can accommodate all data in wide regions of parameter space.
119189999
Signatures of supersymmetry with non-universal Higgs mass at the Large Hadron Collider
A bstractWe discuss large non-universality in the Higgs sector at high scale in supersymmetric theories, in the context of the Large Hadron Collider (LHC). In particular, we note that if $$ {{m}_{{{{H}_u}}}}^2 - {{m}_{{{{H}_d}}}}^2 $$ is large and negative $$ ( \simeq {1}{{0}^{{6}}}{\text{Ge}}{{\text{V}}^{{2}}}) $$ at high scale, the lighter slepton mass eigenstates at the electroweak scale are mostly left chiral, in contrast to a minimal supergravity (mSUGRA) scenario. We utilise this feature to explore different chiral structures of the lowest-lying sleptons, using two methods. First, we study final states with same-sign ditaus. We find that an asymmetry parameter reflecting the polarisation of the taus provides a notable distinction. In addition, we study a charge asymmetry in the jet-lepton invariant mass distribution, arising from decay chains of left-chiral squarks leading to leptons of the first two families.
119226937
Supersymmetry Signals at the LHC under the most favorable SUGRA scenario
Given that it will take quite some time for the Large Hadron Collider (LHC) to reach its desired luminosity, it is important to investigate the most favorable scenario in which supersymmetry (SUSY) may be discovered at the early runs at the LHC. Our aim in this work is to find such a scenario within the gravity mediated SUSY breaking (SUGRA) framework and select a class of final states that warrant a discovery at the very early runs of the LHC. It turns out that such a situation can be associated with a scenario where gluinos are sufficiently light and so are the third generation scalars while the first two family scalars are heavy. We find that this can be achieved from a high-scale set-up with scalar mass non-universality in the third family and gaugino mass non-universality with $M_3 < M_1, M_2$. We show that the final state channels which are most favorable in such a region of parameter space are $4b+{E_{T}}\!\!\!\!/$, $4b+\ell+{E_{T}}\!\!\!\!/$ and $2b+2\ell+{E_{T}}\!\!\!\!/$. We also justify our claim by comparing the results with a minimal supergravity (mSUGRA) scenario with similar gluino mass.
14408151
Signatures of non‐universal gaugino and scalar masses at the Large Hadron Collider (LHC)
We perform a multichannel analysis in context of the Large Hadron Collider (LHC) for supersymmetric (SUSY) theories with high-scale non-universal gaugino masses arising from different non-singlet representations of SU(5) and SO(10) gauge groups in a SUSY-GUT scenario and non-universal scalar masses in form of squark-slepton non-universality, third family scalar non-universality and that arising due to SO(10) D-terms. We present the numerical predictions over a wide region of parameter space using event generator Pythia. Certain broad features emerge from the study which may be useful to identify these non-universal schemes and distinguish them from the minimal supergravity (mSUGRA) framework.
119096880
Constraints on Two-Component Dark Matter
We study 'Higgs Portal' 2-component Dark Matter scenario with two interacting cold Dark Matter (DM) candidates: a neutral scalar singlet ($\varphi$) and a neutral Majorana fermion ($\nu$). The relic abundance of $\varphi$ and $\nu$ is found assuming thermal DM production and solving the Boltzmann equations. We scan over the parameter space of the model to determine regions consistent with the WMAP data for DM relic abundance and the XENON100 direct detection limits for the DM-nucleus cross section.
117279651
Black holes and the positive cosmological constant
We address some aspects of black hole spacetimes endowed with a positive cosmological constant, i.e. black holes located inside a cosmological event horizon. First we establish a general criterion for existence of cosmological event horizons. Using the geometrical set up built for this, we study classical black hole no hair theorems for both static and stationary axisymmetric spacetimes. We discuss cosmic Nielsen-Olesen strings as hair in Schwarzschild-de Sitter spacetime. We also give a general calculation for particle creation by a Killing horizon using complex path analysis and using this we study particle creation in Schwarzschild-de Sitter spacetime by both black hole and the cosmological event horizons.
12947810
Effect of a positive cosmological constant on cosmic strings
We study cosmic Nielsen-Olesen strings in space-times with a positive cosmological constant. For the free cosmic string in a cylindrically symmetric space-time, we calculate the contribution of the cosmological constant to the angle deficit, and to the bending of null geodesics. For a cosmic string in a Schwarzschild-de Sitter space-time, we use Kruskal patches around the inner and outer horizons to show that a thin string can pierce them.
118336392
On the realizability of relativistic acoustic geometry under a generalized perturbation scheme for axisymmetric matter flow onto black holes
We propose a novel linear perturbation scheme to study the stability properties of the stationary transonic integral solutions for axisymmetric matter flow around astrophysical black holes for the Schwarzschild as well as for rotating Rindler space time. We discuss the emergence of the relativistic acoustic geometry as a consequence of such stability analysis. Our work thus makes a crucial connection between two apparently non-overlapping fields of research - the accretion astrophysics and the analogue gravity phenomena.
26054425
Dissipative dynamics of fission in the framework of asymptotic expansion of Fokker-Planck equation

Abstract: The dynamics of fission has been formulated by generalising the asymptotic expansion of the Fokker-Planck equation in terms of the strength of the fluctuations where the diffusion coefficients depend on the stochastic variables explicitly. The prescission neutron multiplicities and mean kinetic energies of the evaporated neutrons have been calculated and compared with the respective experimental data over a wide range of excitation energy and compound nuclear mass. The mean and the variance of the total kinetic energies of the fission fragments have been calculated and compared with the experimental values.
118213552
Acoustic geometry through perturbation of mass accretion rate : I - radial flow in general static spacetime
We propose a novel perturbation scheme to perform the linear stability analysis of stationary transonic integral accretion solutions corresponding to the hydrodynamic non self-gravitating radial flow of matter in a general static black hole spacetime. We demonstrate that a metric independent perturbation scheme can be developed, which leads to the emergence of the relativistic acoustic geometry and ensures the stability of the background stationary solutions. The acoustic metric obtained by perturbing the mass accretion rate rate is found to be identical with that obtained through the perturbation of the velocity potential. Our work thus makes a crucial connection between two apparently disjoint fields of study - accretion astrophysics and analogue gravity phenomena. We also formally prove that acoustic horizons never form in the Rindler spacetime.