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.
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.
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.
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.
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.
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.
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.
118343992
No hair theorems for stationary axisymmetric black holes
AbstractWe present a non-perturbative proof of the no hair theorems corresponding to scalar and Procaﬁelds for stationary axisymmetric de Sitter black hole spacetimes. Our method also applies toasymptotically ﬂat and under a reasonable assumption, to asymptotically anti-de Sitter spacetimes.Keywords: Stationary black holes, no hair theorem, de Sitter 1 Introduction The classical no hair conjecture for black holes states that any gravitational collapse reaches a ﬁnalstationary state characterized only by a small number of parameters. A part of this conjecturehas been proven rigorously by taking diﬀerent matter ﬁelds, known as the no hair theorem (seee.g. [1, 2, 3]) and deals with the uniqueness of stationary black hole solutions characterized onlyby mass, angular momentum, and charges corresponding to long range gauge ﬁelds such as theelectromagnetic ﬁeld. Any non-trivial ﬁeld conﬁguration other than the long range gauge ﬁeldspresent at the exterior of a stationary black hole is known as ‘hair’. In particular, it has beenshown that static, spherically symmetric black holes do not support hair corresponding to scalarsin convex potentials, Proca-massive vector ﬁelds [4], or even gauge ﬁelds corresponding to theAbelian Higgs model [5, 6].All the above proofs assume the spacetime to be asymptotically ﬂat, i.e., one can reach spacelikeinﬁnity so that suﬃciently rapid fall-oﬀ conditions on the matter ﬁelds can be imposed there. Butrecent observations [7, 8] suggest that there is a strong possibility that our universe is endowedwith a small but positive cosmological constant Λ. It is generally expected that in that case thespacetime in its stationary state should have an outer or cosmological Killing horizon [9]. Thecosmological Killing horizon acts in general as a causal boundary (see e.g. [10]) so that no physicalobserver can communicate beyond this horizon along a future directed path. If there is a black
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.