Search results for "proton decay"
showing 10 items of 35 documents
The Minimal Supersymmetric Model without a mu term
2002
We propose a supersymmetric extension of the standard model which is a realistic alternative to the MSSM, and which has several advantages. No ``mu'' supersymmetric Higgs/Higgsino mass parameter is needed for sufficiently heavy charginos. An approximate U(1) R symmetry naturally guarantees that tan beta is large, explaining the top/bottom quark mass hierarchy. This symmetry also suppresses supersymmetric contributions to anomalous magnetic moments, b to s gamma, and proton decay, and these processes place no lower bounds on superpartner masses, even at large tan beta. The soft supersymmetry breaking mass parameters can easily be obtained from either gauge or Planck scale mediation, without …
Two-proton decay of the isobaric analogue state of Ar-31
1998
8 pages, 1 table, 4 figures.-- Journal issue title: "Nucleus-Nucleus Collisions".
Proton radioactivity of117La
2001
A new more precise measurement of the ground-state proton decay of ${}^{117}\mathrm{La}$ is presented $[{E}_{p}=806(5) \mathrm{keV},$ ${t}_{1/2,p}=26(3)$ ms]. ${}^{117}\mathrm{La}$ was produced via the $p4n$ fusion-evaporation channel by bombarding a ${}^{64}\mathrm{Zn}$ target with 310 and 295 MeV ${}^{58}\mathrm{Ni}$ beams. The proton decay rate is consistent with emission from a prolate deformed ${3/2}^{+}$ or ${3/2}^{\ensuremath{-}}$ Nilsson state. No evidence is found for a previously reported proton decay from a high spin isomer in ${}^{117}\mathrm{La}.$ An upper limit for the production cross section for proton decay of ${}^{116}\mathrm{La}$ at a bombarding energy of 325 MeV was esta…
High-spin states beyond the proton drip-line: Quasiparticle alignments in 113 Cs
2014
Abstract Excited states have been studied in the deformed proton emitter 113Cs. Gamma-ray transitions have been unambiguously assigned to 113Cs by correlation with its characteristic proton decay, using the method of recoil-decay tagging. Two previously identified rotational bands have been observed and extended to tentative spins of 45/2 and 51 / 2 ħ , with excitation energies over 8 MeV above the lowest state. These are the highest angular momenta and excitation energies observed to date in any nucleus beyond the proton drip-line. Transitions in the bands have been rearranged compared to previous work. A study of aligned angular momenta, in comparison to the predictions of Woods–Saxon cra…
Shape-changing particle decays ofBi185and structure of the lightest odd-mass Bi isotopes
2004
Proton and alpha decay of the proton-rich nuclide Bi-185 has been restudied in more detail in the complete fusion reaction Nb-93(Mo-95, 3n)Bi-185 at the velocity filter SHIP. The observed decay pat ...
ΔL=3 processes: Proton decay and the LHC
2018
We discuss lepton number violation in three units. From an effective field theory point of view, ΔL=3 processes can only arise from dimension 9 or higher operators. These operators also violate baryon number, hence many of them will induce proton decay. Given the high dimensionality of these operators, in order to have a proton half-life in the observable range, the new physics associated to ΔL=3 processes should be at a scale as low as 1 TeV. This opens up the possibility of searching for such processes not only in proton decay experiments but also at the LHC. In this work we analyze the relevant d=9, 11, 13 operators which violate lepton number in three units. We then construct one simple…
Structure and prospects of the simplest SO(10) GUTs
2012
We recapitulate the latest results on the class of the simplest SO(10) grand unified models in which the GUT-scale symmetry breaking is triggered by an adjoint Higgs representation. We argue that the minimal survival approximation traditionally used in the GUT- and seesaw-scale estimates tends to be blind to very interesting parts of the parameter space in which some of the intermediate-scale states necessary for non-supersymmetric unification of the SM gauge couplings can be as light as to leave their imprints in the TeV domain. The stringent minimal-survival-based estimates of the B-L scale are shown to be relaxed by as much as four orders of magnitude, thus admitting for a consistent imp…
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.
Proton Decay of an Intruder State inB185i
1996
The new proton radioactivity ${}^{185m}\mathrm{Bi}$ has been observed, produced via the ${}^{95}\mathrm{Mo}{(}^{92}\mathrm{Mo},pn{)}^{185}\mathrm{Bi}$ reaction. Its decay proceeds from the low-lying ${\frac{1}{2}}^{+}$ intruder state in ${}^{185}\mathrm{Bi}$ to the ${}^{184}\mathrm{Pb}$ ground state with the emission of a proton of energy $1.585\ifmmode\pm\else\textpm\fi{}0.009\mathrm{MeV}$ and a half-life of $44\ifmmode\pm\else\textpm\fi{}16\ensuremath{\mu}\mathrm{s}$. This marks the first observation of proton radioactivity above the $Z\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}82$ closed shell, and it has been used to obtain the admixture of a ${0}^{+}$ intruder state in ${}^{184…
LHC-scale left-right symmetry and unification
2013
We construct a comprehensive list of nonsupersymmetric standard model extensions with a low-scale left-right (LR)-symmetric intermediate stage that may be obtained as simple low-energy effective theories within a class of renormalizable SO(10) grand unified theories. Unlike the traditional minimal LR models many of our example settings support a perfect gauge coupling unification even if the LR scale is in the LHC domain at a price of only (a few copies of) one or two types of extra fields pulled down to the TeV-scale ballpark. We discuss the main aspects of a potentially realistic model building conforming the basic constraints from the quark and lepton sector flavor structure, proton deca…