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.
13952788
Non-universal gaugino masses: a signal-based analysis for the Large Hadron Collider
We study the possible signatures of non-universal scalar masses in supersymmetry at the Large Hadron Collider (LHC). This is done, following our recent study on gaugino non-universality, via a multichannel analysis, based largely on the ratios of event rates for different final states, aimed at minimizing irregularity in the pattern due to extraneous effects and errors. We have studied (a) squark-slepton non-universality, (b) non-universality in sfermion masses of the third family, (c) the effects of SO(10) D-terms in supersymmetric Grand Unified Theories. After presenting an elaborate numerical analysis of likeand opposite-sign dileptons, inclusive and hadronically quiet trileptons as well as inclusive jet final states, we point out specific features of the spectrum in each case, which can be differentiated in the above channels from the spectrum for a minimal supergravity scenario with a universal scalar mass at high scale. The event selection criteria, and the situations where the signals are sizable enough for a comparatve study, are also delineated. It is found that, with some exceptions, the trilepton channels are likely to be especially useful for this purpose.
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.
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.
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.
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.
119217317
Note on black hole no hair theorems for massive forms and spin-1/2 fields
We give a proof of the non-perturbative no hair theorems for a massive 2-form field with 3-form field strength for general stationary axisymmetric and static (anti)-de Sitter or asymptotically flat black hole spacetimes with some suitable geometrical properties. The generalization of this result for higher form fields is discussed. Next, we discuss the perturbative no hair theorems for massive spin-1/2 fields for general static backgrounds with electric or magnetic charge. Some generalization of this result for stationary axisymmetric spacetimes are also discussed. All calculations are done in arbitrary spacetime dimensions.
118575846
Massive spin-2 and spin-1/2 no hair theorems for stationary axisymmetric black holes
We present a proof of the no hair theorems corresponding to free massive non-perturbative PauliFierz spin-2 and perturbative massive spin- 1 fields for stationary axisymmetric de Sitter black hole spacetimes of dimension four with two commuting Killing vector fields. The applicability of these results for asymptotically flat and anti-de Sitter spacetimes are also discussed.
14552385
Gödel black hole, closed timelike horizon and the study of particle emissions
We show that a particle, with positive orbital angular momentum, following an outgoing null/timelike geodesic, shall never reach the closed timelike horizon present in the (4 + 1)-dimensional rotating Gödel black hole space–time. Therefore a large part of this space–time remains inaccessible to a large class of geodesic observers, depending on the conserved quantities associated with them. We discuss how this fact and the existence of the closed timelike curves present in the asymptotic region make the quantum field theoretic study of the Hawking radiation, where the asymptotic observer states are a pre-requisite, unclear. However, the semi classical approach provides an alternative to verify the Smarr formula derived recently for the rotating Gödel black hole. We present a systematic analysis of particle emissions, specifically for scalars, charged Dirac spinors and vectors, from this black hole via the semiclassical complex path method.
18344805
A Dynamical study of fission process and estimation of prescission neutron multiplicity
The dynamics of fission has been studied by solving Euler-Lagrange equation with dissipation generated through one and two body nuclear friction. The average kinetic energies of the fission fragments, prescission neutron multiplicities and the mean energies of the prescission neutrons have been calculated and compared with experimental values and they agree quite well. A single value of friction coefficient has been used to reproduce the experimental data for both symmetric and asymmetric splitting of the fissioning systems over a wide range of masses and excitation energies. It has been observed that a stronger friction is required in the saddle to scission region as compared to that in the ground state to saddle region.
118446121
Mass function and particle creation in Schwarzschild–de Sitter spacetime
We construct a mass or energy function for the non-Nariai class Schwarzschild–de Sitter black hole spacetime in the region between the black hole and the cosmological event horizons. The mass function is local, positive definite, continuous and increases monotonically with the radial distance from the black hole event horizon. We derive the Smarr formula using this mass function, and demonstrate that the mass function reproduces the two-temperature Schwarzschild–de Sitter black hole thermodynamics, along with a term corresponding to the negative pressure due to positive cosmological constant. We further give a field theoretic derivation of the particle creation by both the horizons and discuss its connection with the mass function.