اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدPrediction of $htogamma Z$ from $htogammagamma$ at LHC for the IMDS$_3$ Model
327
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We consider the decays $htogammagamma,gamma Z$ in the context of an extension of the standard model with two inert doublets and an additional $S_3$ symmetry. This model has contributions for these processes through new charged scalar-loops. Comparing our $htogammagamma$ with the more precise available experimental data we can predict the behaviour of $htogamma Z$ due that they depend on the same parameters, our estimation for this channel is 1.05 times the standard model value, but can be up to 1.16 if consider the $+1sigma$ uncertainty from the $htogammagamma$ data, and down to 0.96 if consider $-1sigma$.
قيم البحث
اقرأ أيضاً
We study the LHC sensitivity to probe a long-lived heavy neutrino $N$ in the context of $Z$ models. We focus on displaced vertex signatures of $N$ when pair produced via a $Z$, decaying to leptons and jets inside the inner trackers of the LHC experim
ents. We explore the LHC reach with current long-lived particle search strategies for either one or two displaced vertices in association with hadronic tracks or jets. We focus on two well-motivated models, namely, the minimal $U(1)_{B-L}$ scenario and its $U(1)_{X}$ extension. We find that searches for at least one displaced vertex can cover a significant portion of the parameter space, with light-heavy neutrino mixings as low as $|V_{lN}|^2approx 10^{-17}$, and $l=e,mu$ accessible across GeV scale heavy neutrino masses.
We study the phenomenology of the neutral gauge sector of the four-site Higgsless model, based on the SU(2)_L x SU(2)_1 x SU(2)_2 x U(1)_Y gauge symmetry, at present colliders. The model predicts the existence of two neutral and four charged extra ga
uge bosons, Z_{1,2} and W^pm_{1,2}. We expand and update a previous study, by concentrating on the neutral sector. We derive new limits on Z_{1,2}-boson masses and couplings from recent direct searches at the Tevatron. We moreover estimate the discovery potential at the Tevatron with a project luminosity L=10 fb^{-1}, and at the 7 TeV LHC with L=1 fb^{-1}. In contrast to other Higgsless theories characterized by almost fermiophobic extra gauge bosons, the four-site model allows sizeable Z_{1,2}-boson couplings to SM fermions. Owing to this feature, we find that in the next two years the extra Z_{1,2}-bosons could be discovered in the favoured Drell-Yan channel at the 7 TeV LHC for Z_{1,2} masses in the TeV region, depending on model parameters.
Electrically-neutral massive color-singlet and color-octet vector bosons, which are often predicted in Beyond the Standard Model theories, have the potential to be discovered as dijet resonances at the LHC. A color-singlet resonance that has leptopho
bic couplings needs further investigation to be distinguished from a color-octet one. In previous work, we introduced a method for discriminating between the two kinds of resonances when their couplings are flavor-universal, using measurements of the dijet resonance mass, total decay width and production cross-section. Here, we describe an extension of that method to cover a more general scenario, in which the vector resonances could have flavor non-universal couplings; essentially, we incorporate measurements of the heavy-flavor decays of the resonance into the method. We present our analysis in a model-independent manner for a dijet resonance with mass 2.5-6.0 TeV at the LHC with $sqrt{s}=14$ TeV and integrated luminosities 30, 100, 300 and 1000 ${rm fb}^{-1}$, and show that the measurements of the heavy-flavor decays should allow conclusive identification of the vector boson. Note that our method is generally applicable even for a Z boson with non-Standard invisible decays. We include an appendix of results for various resonance couplings and masses to illustrate how well each observable must be measured to distinguish colorons from Z bosons.
Models with a non-universal Z exhibit in general flavor changing neutral currents (FCNC) at tree-level. When the Z couplings favor the third generation, flavor changing transitions of the form Ztc and Ztu could be large enough to be observable at the
LHC. In this paper we explore this possibility using the associated production of a single top-quark with the Z and find that integrated luminosities of a few hundred fb$^{-1}$ are necessary to probe the interesting region of parameter space.
Extending the Standard Model (SM) by a $U(1)_{L_mu-L_tau}$ group gives potentially significant new contributions to $g_mu-2$, allows the construction of realistic neutrino mass matrices, incorporates violation of lepton universality violation, and of
fers an anomaly-free mediator for a Dark Matter (DM) sector. In a recent analysis we showed that published LHC searches are not very sensitive to this model. Here we apply several Machine Learning (ML) algorithms in order to distinguish this model from the SM using simulated LHC data. In particular, we optimize the $3mu$-signal, which has a considerably larger cross section than the $4mu$-signal. Furthermore, since the $2$-muon plus missing $E_T$ final state gets contributions from diagrams involving DM particles, we optimize it as well. We find greatly improved sensitivity, which already for $36$ fb$^{-1}$ of data exceeds the combination of published LHC and non-LHC results. We also emphasize the usefulness of Boosted Decision Trees which, unlike Neural Networks, easily allow to extract additional information from the data which directly connect to the theoretical model. The same scheme could be used to analyze other models.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
