اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدStudy of the lepton flavor-violating $Ztotaumu$ decay
121
0
0.0
(
0
)
تأليف
J. I. Aranda
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The lepton flavor violating $Z^{prime}totaumu$ decay is studied in the context of several extended models that predict the existence of the new gauge boson named $Z^prime$. A calculation of the strength of the lepton flavor violating $Z^primemutau$ coupling is presented by using the most general renormalizable Lagrangian that includes lepton flavor violation. We used the experimental value of the muon magnetic dipole moment to bound this coupling, from which the $mathrm{Re}(Omega_{Lmutau}Omega^ast_{Rmutau})$ parameter is constrained and it is found that $mathrm{Re}(Omega_{Lmutau}Omega^ast_{Rmutau})sim 10^{-2}$ for a $Z^prime$ boson mass of 2 TeV. Alongside, we employed the experimental restrictions over the $tautomugamma$ and $tautomumu^+mu^-$ processes in the context of several models that predict the existence of the $Z^prime$ gauge boson to bound the mentioned coupling. The most restrictive bounds come from the calculation of the three-body decay. For this case, it was found that the most restrictive result is provided by a vector-like coupling, denoted as $|Omega_{mutau}|^2$, for the $Z_chi$ case, finding around $10^{-2}$ for a $Z^prime$ boson mass of 2 TeV. We used this information to estimate the branching ratio for the $Z^primetotaumu$ decay. According to the analyzed models the least optimistic result is provided by the Sequential $Z$ model, which is of the order of $10^{-2}$ for a $Z^prime$ boson mass around 2 TeV.
قيم البحث
اقرأ أيضاً
This dissertation reviews the Standard Model formalism as well as the Lepton Flavour Violating (LFV) decay processes which cause its extension, known as the physics beyond the SM. Firstly, using the experimental bounds on three body LFV decays, the c
orresponding bounds on two body LFV decays are reviewed. The dynamical suppression of three body LFV decays due to momentum dependent couplings is also reviewed. Secondly, the role of the LFV decays to explain the LSND excess is discussed in detail, for which the experimental bounds on three body LFV decays, i.e. mu -> 3e are used to constraint the coupling tilde{g}_{Z_{mu e}}, which is needed to calculate the anomalous muon decay mu -> e u_lbar{ u}_l. Then comparing the effective coupling of anomalous muon decay to r>1.6times 10^{-3} [9809524], it is proved that LFV is not the correct hypothesis to explain the LSND excess. Finally, LFV decays at loop order are studied in Seesaw model of neutrino masses [PRL. 86 2502 (2001)] where the smallness of the Seesaw neutrino mass may be naturally realized with m_N (mass of right-handed singlet neutrinos) of order 1 TeV. It is shown that the Higgs mass of a new scalar doublet with lepton number L=-1 needed in the model has to be larger than 50 TeV to get the branching ratio of mu -> 3e to be consistent with the existing bound on mu -> 3e. This defeats the original motivation of the model, namely that there is no physics beyond the TeV energy scale.
We study the lepton flavor violating (LFV) decays Z-> l_i l_j (l_{i,j}=e,mu,tau) in the framework of the minimal 331 model. The main contributions arise at the one-loop level via a doubly charged bilepton with general LFV couplings. We obtain an esti
mate for the corresponding branching ratios by using the bounds on the LFV couplings of the doubly charged bilepton from the current experimental limits on the decays l_i-> l_jgamma and l_i-> l_j l_k l_k. A bound on the bilepton mass is also obtained through the current limit on the anomalous magnetic moment of the muon. It is found that the bilepton contributions to LFV Z decays are not expected to be at the reach of experimental detection. In particular, the branching ratio for the Z-> mu tau decay is below the 10^{-10} level for a bilepton mass of the order of 500 GeV.
Exotic Higgs decays are promising channels to discover new physics in the near future. We present a simple model with a new light scalar that couples to the Standard Model through a charged lepton-flavor violating interaction. This can yield exciting
new signatures, such as $h to e^+ e^+ mu^-mu^-$, that currently have no dedicated searches at the Large Hadron Collider. We discuss this model in detail, assess sensitivity from flavor constraints, explore current constraints from existing multi-lepton searches, and construct a new search strategy to optimally target these exotic, lepton-flavor violating Higgs decays.
A search for the charged lepton flavor violating decay $J/psito e^{pm}tau^{mp}$ with $tau^{mp} to pi^{mp}pi^0 u_{tau}$ is performed with about $10$ billion $J/ psi$ events collected with the BESIII detector at the BEPCII. No significant signal is obs
erved, and an upper limit is set on the branching fraction $mathcal{B}(J/psito e^{pm}tau^{mp})<7.5times10^{-8}$ at the 90$%$ confidence level. This improves the previously published limit by two orders of magnitude.
We investigate how observations of the lepton flavor violating decay of the Higgs boson ($h to ellell^prime$) can narrow down models of neutrino mass generation mechanisms, which were systematically studied in Refs. [1,2] by focusing on the combinati
on of new Yukawa coupling matrices with leptons. We find that a wide class of models for neutrino masses can be excluded if evidence for $h to ellell^prime$ is really obtained in the current or future collider experiments. In particular, simple models of Majorana neutrino masses cannot be compatible with the observation of $h to ellell^prime$. It is also found that some of the simple models to generate masses of Dirac neutrinos radiatively can be compatible with a significant rate of the $h to ellell^prime$ process.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
