Search results for "Number"
showing 10 items of 3939 documents
Proposal for generalised supersymmetry Les Houches Accord for see-saw models and PDG numbering scheme
2013
The SUSY Les Houches Accord (SLHA) 2 extended the first SLHA to include various generalisations of the Minimal Supersymmetric Standard Model (MSSM) as well as its simplest next-to-minimal version. Here, we propose further extensions to it, to include the most general and well-established see-saw descriptions (types I/II/III, inverse, and linear) in both an effective and a simple gauged extension of the MSSM framework. In addition, we generalise the PDG numbering scheme to reflect the properties of the particles
Analysis of light neutrino exchange and short-range mechanisms in 0νββ decay
2020
Neutrinoless double beta decay (0νββ) is a crucial test for lepton number violation. Observation of this process would have fundamental implications for neutrino physics, theories beyond the Standard Model and cosmology. Focusing on so-called short-range operators of 0νββ and their potential interplay with the standard light Majorana neutrino exchange, we present the first complete calculation of the relevant nuclear matrix elements, performed within the interacting boson model (IBM-2). Furthermore, we calculate the relevant phase space factors using exact Dirac electron wave functions, taking into account the finite nuclear size and screening by the electron cloud. The obtained numerical r…
R-Parity Breaking in Minimal Supergravity
1999
We consider the Minimal Supergravity Model with universality of scalar and gaugino masses plus an extra bilinear term in the superpotential which breaks R-Parity and lepton number. We explicitly check the consistency of this model with the radiative breaking of the electroweak symmetry. A neutrino mass is radiatively induced, and large Higgs-Lepton mixings are compatible with its experimental bound. We also study briefly the lightest Higgs mass. This one-parameter extension of SUGRA-MSSM is the simplest way of introducing R-parity violation.
Towards a New Minimal SO(10) Unification
2012
We argue that non-supersymmetric SO(10) models based on a renormalizable Higgs sector in which spontaneous symmetry breaking is triggered by the VEVs of a 45-dimensional adjoint and a 126-dimensional tensor representations can provide a potentially realistic yet relatively simple framework for a future robust estimate of the proton lifetime. Following closely the work Phys.Rev.D85, 095014 (2012), arXiv: 1202.0807 [hep-ph] we comment on the gauge unification constraints on the B-L breaking scale and show that there are several regions in the parameter space of the minimal model where the seesaw scale in the phenomenologically favoured ballpark of around 10^13-14 GeV is consistently supported.
Traces of the hidden-charm S=−1 pentaquark in the Λb→J/ΨηΛ decay
2017
The hidden charm pentaquark state Pc (4450), observed recently by the LHCb collaboration in the Λb →J/ψK − p decay, may be of molecular nature, as advocated by some unitary approaches that also predict pentaquark partners in the strangeness S=−1 sector. In this work we argue that a hidden-charm strange pentaquark could also be seen in the decay of theΛb , but through the J/ψη Λ decay mode, by studying the invariant mass spectrum of J/ψ Λ pairs.In our model we assume a standard weak decay topology, then incorporate the hadronization process and final state interaction effects, and we find that the J/ψη Λ final state is populated with the strength similar to that of the J/ψK− p . We have stud…
Leptogenesis with small violation of B-L
2012
We analyze leptogenesis in the context of seesaw models with almost conserved lepton number, focusing on the L-conserving contribution to the flavoured CP asymmetries. We find that, contrary to previous claims, successful leptogenesis is feasible for masses of the lightest heavy neutrino as low as M1 ~ 10^6 GeV, without resorting to the resonant enhancement of the CP asymmetry for strongly degenerate heavy neutrinos. This lower limit renders thermal leptogenesis compatible with the gravitino bound in supersymmetric scenarios.
Nuclear physics of non-standard 0νβ β-decay
2019
The observation neutrinoless double beta (0νβ β) decay remains crucial for understanding lepton number violation. In view of the difficulties to observe the mass mechanism of 0νβ β-decay, investigations of other mechanisms are in order. These non-standard mechanisms can be divided into short-range and long-range mechanisms. Recently, we have started systematic study for all possible short-range and long-range non-standard mechanisms. The aim of this study is twofold: I) to provide explicit formulas for the nuclear matrix elements (NMEs) and phase-space factors (PSFs) from which the decay rate for one or a combination of mechanisms operating at the same time can be calculated; II) to provide…
News in Charged-Composite Particle Scattering: Theory and Applications
2003
A brief summary is given of recent developments in the theory of charged-composite particle scattering, and of practical applications.
Synchronizing Quantum Harmonic Oscillators through Two-Level Systems
2017
Two oscillators coupled to a two-level system which in turn is coupled to an infinite number of oscillators (reservoir) are considered, bringing to light the occurrence of synchronization. A detailed analysis clarifies the physical mechanism that forces the system to oscillate at a single frequency with a predictable and tunable phase difference. Finally, the scheme is generalized to the case of $N$ oscillators and $M(<N)$ two-level systems.
Interplay of order-disorder phenomena and diffusion in rigid binary alloys in the presence of vacancies: Monte Carlo simulations
2006
Transport phenomena are studied for a binary $(AB)$ alloy on a rigid square lattice with nearest-neighbor attraction between unlike particles, assuming a small concentration ${c}_{v}$ of vacancies $V$ being present, to which $A$ $(B)$ particles can jump with rates ${\ensuremath{\Gamma}}_{A}$ $({\ensuremath{\Gamma}}_{B})$ in the case where the nearest-neighbor attractive energy ${ϵ}_{AB}$ is negligible in comparison with the thermal energy ${k}_{B}T$ in the system. This model exhibits a continuous order-disorder transition for concentrations ${c}_{A},{c}_{B}=1\ensuremath{-}{c}_{A}\ensuremath{-}{c}_{V}$ in the range ${c}_{A,1}^{\mathit{crit}}\ensuremath{\leqslant}{c}_{A}\ensuremath{\leqslant}…