14407716
Nonuniversal scalar masses: A signal-based analysis for the CERN Large Hadron Collider
We study the possible signatures of nonuniversal scalar masses in supersymmetry at the Large Hadron Collider (LHC). This is done, following our recent study on gaugino nonuniversality, 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 nonuniversality, (b) nonuniversality 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 like- and 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 comparative study, are also delineated. It is found that, with some exceptions, the trilepton channels are likely to be especially useful for this purpose.
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.
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.
10611151
Unitarity violation in sequential neutrino mixing in a model of extra dimensions
We give the first demonstration of unitarity violation in the sequential neutrino mixing matrix in a scenario with extra compact spacelike dimensions. Gauge singlet neutrinos are assumed to propagate in one extra dimension, giving rise to an infinite tower of states in the effective four-dimensional theory. It is shown that this leads to small lepton-number violating entries in the neutrino mass matrix, which can violate unitarity on the order of 1%.
55809021
Heptagonic symmetry for quarks and leptons
The non-Abelian discrete symmetry D(7) of the heptagon is successfully applied to both quark and lepton mass matrices, including CP violation.
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.
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.
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.
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.
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.
59390019
Can a black hole with conformal scalar hair rotate
It is shown that, under the separability assumption for the metric, the slow-rotation approximation for the Bocharova-Bronnikov-Melnikov-Bekenstein black hole in general relativity with a conformally coupled scalar field does not work outside the event horizon. Suggestions indicated by our present analysis towards a fully rotating black hole solution are discussed.