اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدA two-Higgs-doublet interpretation of a small Tevatron $Wjj$ excess
32
0
0.0
(
0
)
تأليف
John F. Gunion
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We show that a $Wjj$ excess in Tevatron data could be explained in the context of the standard non-supersymmetric two-Higgs-doublet model for appropriately chosen parameters. Correlated signals in the $gammagamma$ and $W^+ W^- b anti b$ final states are predicted and are on the verge of being detectable. The proposed model is most attractive if the cross section for the $Wjj$ excess is $lsim 1-2pb$.
قيم البحث
اقرأ أيضاً
We consider a simple extension of the type-II two-Higgs-doublet model by introducing a real scalar as a candidate for dark matter in the present Universe. The main annihilation mode of the dark matter particle with a mass of around $31-40$ GeV is int
o a $bbar{b}$ pair, and this annihilation mode suitably explains the observed excess of the gamma-ray flux from the Galactic Center. We identify the parameter region of the model that can fit the gamma-ray excess and satisfy phenomenological constraints, such as the observed dark matter relic density and the null results of direct dark matter search experiments. Most of the parameter region is found to be within the search reach of future direct dark matter detection experiments.
We analyse various flavour changing processes like $tto hu,hc$, $hto tau e,taumu$ as well as hadronic decays $hto bs,bd$, in the framework of a class of two Higgs doublet models where there are flavour changing neutral scalar currents at tree level.
These models have the remarkable feature of having these flavour-violating couplings entirely determined by the CKM and PMNS matrices as well as $tanbeta$. The flavour structure of these scalar currents results from a symmetry of the Lagrangian and therefore it is natural and stable under the renormalization group. We show that in some of the models the rates of the above flavour changing processes can reach the discovery level at the LHC at 13 TeV even taking into account the stringent bounds on low energy processes, in particular $muto egamma$.
Motivated by an anomaly in $R(D^{(*)})={rm BR}(bar{B}rightarrow D^{(*)} tau^-bar{ u})/{rm BR}(bar{B}rightarrow D^{(*)} l^-bar{ u})$ reported by BaBar, Belle and LHCb, we study $R(D^{(*)})$ in a general two Higgs doublet model (2HDM). Although it has
been suggested that it is difficult for the 2HDM to explain the current world average for $R(D^{(*)})$, it would be important to clarify how large deviations from the standard model predictions for $R(D^{(*)})$ are possible in the 2HDM. We investigate possible corrections to $R(D^{(*)})$ in the 2HDM by taking into account various flavor physics constraints (such as $B_c^-rightarrow tau^- bar{ u}$, $brightarrow sgamma$, $brightarrow s l^+l^-$, $Delta m_{B_{d,s}}$, $B_srightarrow mu^+mu^-$ and $tau^+tau^-$, and $B^-rightarrow tau^- bar{ u}$), and find that it would be possible (impossible) to accommodate the 1$sigma$ region suggested by the Belles result when we adopt a constraint ${rm BR}(B_c^-rightarrow tau^- bar{ u})le30~%$ (${rm BR}(B_c^-rightarrow tau^- bar{ u})le10~%$). We also study productions and decays of heavy neutral and charged Higgs bosons at the Large Hadron Collider (LHC) experiment and discuss the constraints and implications at the LHC. We show that in addition to well-studied production modes $bgrightarrow tH^-$ and $ggrightarrow H/A$, exotic productions of heavy Higgs bosons such as $cgrightarrow bH^+,t+H/A$ and $cbar{b}rightarrow H^+$ would be significantly large, and the search for their exotic decay modes such as $H/Arightarrow tbar{c}+cbar{t},~mu^pmtau^mp$ and $H^+rightarrow cbar{b}$ as well as $H/Arightarrow tau^+tau^-$ and $H^+rightarrow tau^+ u$ would be important to probe the interesting parameter regions for $R(D^{(*)})$.
We make an attempt to identify regions in a Type II Two-Higgs Doublet Model, which correspond to a metastable electroweak vacuum with lifetime larger than the age of the universe. We analyse scenarios which retain perturbative unitarity up to Grand u
nification and Planck scales. Each point in the parameter space is restricted using Data from the Large Hadron Collider (LHC) as well as flavor and precision electroweak constraints. We find that substantial regions of the parameter space are thus identified as corresponding to metastability, which compliment the allowed regions for absolute stability, for top quark mass at the high as well as low end of its currently allowed range. Thus, a two-Higgs doublet scenario with the electroweak vacuum, either stable or metastable, can sail through all the way up to the Planck scale without facing any contradictions.
We propose a gauged two-Higgs-doublet model (2HDM) featuring an anomalous Peccei-Quinn symmetry, $U(1)_{PQ}$. Dangerous tree-level flavour-changing neutral currents, common in 2HDMs, are forbidden by the extra gauge symmetry, $U(1)_X$. In our constru
ction, the solutions to the important issues of neutrino masses, dark matter and the strong CP problem are interrelated. Neutrino masses are generated via a Dirac seesaw mechanism and are suppressed by the ratio of the $U(1)_X$ and the $U(1)_{PQ}$ breaking scales. Naturally small neutrino masses suggest that the breaking of $U(1)_X$ occurs at a relatively low scale, which may lead to observable signals in near-future experiments. Interestingly, spontaneous symmetry breaking does not lead to mixing between the $U(1)_X$ gauge boson, $Z^prime$, and the standard $Z$. For the expected large values of the $U(1)_{PQ}$ scale, the associated axion becomes invisible, with DFSZ-like couplings, and may account for the observed abundance of cold dark matter. Moreover, a viable parameter space region, which falls within the expected sensitivities of forthcoming axion searches, is identified. We also observe that the flavour-violating process of kaon decaying into pion plus axion, $K^+ to pi^+ a$, is further suppressed by the $U(1)_X$ scale, providing a rather weak lower bound for the axion decay constant $f_a$.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
