ترغب بنشر مسار تعليمي؟ اضغط هنا

Dynamical R-parity Breaking at the LHC

69   0   0.0 ( 0 )
 نشر من قبل Yue Zhang
 تاريخ النشر 2010
  مجال البحث
والبحث باللغة English




اسأل ChatGPT حول البحث

In a class of extensions of the minimal supersymmetric standard model with (B-L)/left-right symmetry that explains the neutrino masses, breaking R-parity symmetry is an essential and dynamical requirement for successful gauge symmetry breaking. Two consequences of these models are: (i) a new kind of R-parity breaking interaction that protects proton stability but adds new contributions to neutrinoless double beta decay and (ii) an upper bound on the extra gauge and parity symmetry breaking scale which is within the large hadron collider (LHC) energy range. We point out that an important prediction of such theories is a potentially large mixing between the right-handed charged lepton ($e^c$) and the superpartner of the right-handed gauge boson ($widetilde W_R^+$), which leads to a brand new class of R-parity violating interactions of type $widetilde{mu^c}^dagger u_mu^c e^c$ and $widetilde{d^c}^daggeru^c e^c$. We analyze the relevant constraints on the sparticle mass spectrum and the LHC signatures for the case with smuon/stau NLSP and gravitino LSP. We note the smoking gun signals for such models to be lepton flavor/number violating processes: $ppto mu^pmmu^pm e^+e^-jj$ (or $tau^pmtau^pm e^+e^-jj$) and $pptomu^pm e^pm b bar{b} jj$ (or $tau^pm e^pm b bar{b} jj$) without significant missing energy. The predicted multi-lepton final states and the flavor structure make the model be distinguishable even in the early running of the LHC.

قيم البحث

اقرأ أيضاً

The $R$-parity violating decays of Bino neutralino LSPs are analyzed within the context of the $B-L$ MSSM heterotic standard model. These LSPs correspond to statistically determined initial soft supersymmetry breaking parameters which, when evolved u sing the renormalization group equations, lead to an effective theory satisfying all phenomenological requirements; including the observed electroweak vector boson masses and the Higgs mass. The explicit RPV decay channels of these LSPs into standard model particles, the analytic and numerical decay rates and the associated branching ratios are presented. The analysis of these quantities breaks into two separate calculations; first, for Bino neutralino LSPs with mass larger than $M_{W^{pm}}$ and, second, when the Bino neutralino mass is smaller than the electroweak scale. The RPV decay processes in both of these regions is analyzed in detail. The decay lengths of these RPV interactions are discussed. It is shown that for heavy Bino neutralino LSPs the vast majority of these decays are prompt, although a small, but calculable, number correspond to displaced decays of various lengths. The situation is reversed for light Bino LSPs, only a small number of which can RPV decay promptly. The relation of these results to the neutrino hierarchy--either normal or inverted--is discussed in detail.
The scalar partner of the top quark (the stop) is relatively light in many models of supersymmetry breaking. We study the production of stops at the Large Hadron Collider (LHC) and their subsequent decays through baryon-number violating couplings suc h that the final state contains no leptons. A detailed analysis performed using detector level observables demonstrate that stop masses upto $sim 600 gev$ may be explored at the LHC depending on the branching ratios for such decays and the integrated luminosity available. Extended to other analogous scenarios, the analysis will, generically, probe even larger masses.
We consider the case where supersymmetry with broken R-parity is embedded in the minimal supergravity model (mSUGRA). This alters the standard mSUGRA spectrum and opens a wide range in parameter space, where the scalar tau is the lightest supersymmet ric particle, instead of the lightest neutralino. We study the resulting LHC phenomenology. Promising signatures would be detached vertices from long-lived staus, multi lepton final states and multi-tau final states. We investigate in detail the corresponding cross sections and decay rates in characteristic benchmark scenarios.
The $R$-parity violating decays of both Wino chargino and Wino neutralino LSPs are analyzed within the context of the $B-L$ MSSM heterotic standard model. These LSPs correspond to statistically determined initial soft supersymmetry breaking parameter s which, when evolved using the renormalization group equations, lead to an effective theory satisfying all phenomenological requirements; including the observed electroweak vector boson and Higgs masses. The explicit decay channels of these LSPs into standard model particles, the analytic and numerical decay rates and the associated branching ratios are presented. The decay lengths of these RPV interactions are discussed. It is shown that the vast majority of these decays are prompt, although a small, but calculable, number correspond to displaced vertices of various lengths. It is demonstrated that for a Wino chargino LSP, the NLSP is the Wino neutralino with a mass only slightly higher than the LSP-- and vice-versa. As a consequence, we show that both the Wino chargino and Wino neutralino LSP/NLSP $R$-parity violating decays should be simultaneously observable at the CERN LHC.
We study the collider phenomenology of bilinear R-parity violating supergravity, the simplest effective model for supersymmetric neutrino masses accounting for the current neutrino oscillation data. At the CERN Large Hadron Collider the center-of-mas s energy will be high enough to probe directly these models through the search for the superpartners of the Standard Model (SM) particles. We analyze the impact of R-parity violation on the canonical supersymmetry searches - that is, we examine how the decay of the lightest supersymmetric particle (LSP) via bilinear R-parity violating interactions degrades the average expected missing momentum of the reactions and show how this diminishes the reach in the usual channels for supersymmetry searches. However, the R-parity violating interactions lead to an enhancement of the final states containing isolated same-sign di-leptons and trileptons, compensating the reach loss in the fully inclusive channel. We show how the searches for displaced vertices associated to LSP decay substantially increase the coverage in supergravity parameter space, giving the corresponding reaches for two reference luminosities of 10 and 100 fb$^{-1}$ and compare with those of the R-parity conserving minimal supergravity model.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا