In this paper, we investigate the time-dependent angular analysis of $B_s^0 \rightarrow ϕϕ$ decay to search for new physics signals via CP-violating observables. We work with a new physics Hamiltonian containing both left- and right-handed Chromomagnetic dipole operators. The hierarchy of the helicity amplitudes in this model gives us a new scheme of experimental search, which is different from the ones LHCb has used in its analysis. To illustrate this new scheme, we perform a sensitivity study using two pseudo datasets generated using LHCb's measured values. We find the sensitivity of CP-violating observables to be of the order of $5-7\%$ with the current LHCb statistics. Moreover, we show that Belle(II)'s $B^0_d \rightarrow ϕK_s$ and LHCb's $B_s^0 \rightarrow ϕϕ$ measurements could be coupled within our model to obtain the chirality of the new physics.
New physics in the chromomagnetic flavor changing transition s->dg* can avoid the strong GIM suppression of the Standard Model and lead to large contributions to CP-violating observables, in particular to the epsilon' parameter, that we address here. We discuss the case of the Left-Right symmetric models, where this contribution implies bounds on the phases of the right-handed quark mixing matrix, or in generic models with large phases a strong bound on the Left-Right symmetry scale. To the leading order, a numeric formula for epsilon' as a function of the short-distance coefficients for a wid…
We discuss on the search for the right-handed weak interaction effects in the SU(2)$_L \times$SU(2)$_R$ model with lepton doublets $(ν_\ell, \ell^-)_L$ and $(N_\ell, \ell^-)_R$ ($\ell = e, μ, τ)$. We will point out that only the chance of the observation of the right-handed weak interaction effect will be in the rare decay $K^+ \rightarrow π^- μ^+ μ^+$.
In many models incorporating the type-I seesaw mechanism, the right-handed neutrino ($N$) couples to heavy vector/scalar bosons and thereby has resonant pair production. It barely receives attention thus far, however, it may provide the best avenue to probe TeV scale $N$ without requiring anomalously large mixing between $N$ and the active neutrino $ν_L$. In this paper we explore the discovery prospects of (mainly heavy) $N$ pair production at the 14 TeV LHC and future 100 TeV $pp$ collider, based on the three signatures: 1) trilepton from $ N(\rightarrow \ell W_\ell)N(\rightarrow \ell W_h)$ w…
We perform a detailed study of the signal rate of the lightest Higgs boson in the diphoton channel ($μ_{γγ}$), recently analyzed by both the ATLAS and CMS collaborations at the Large Hadron Collider, in the framework of $U(1)_R-$ lepton number model with a right handed neutrino superfield. The corresponding neutrino Yukawa coupling, `$f$', plays a very important role in the phenomenology of this model. A large value of $f\sim\mathcal O(1)$ provides an additional tree level contribution to the lightest Higgs boson mass along with a very light (mass $\sim$ a few hundred MeV) bino like neutralino…
We examine lepton flavor violating (LFV) interactions for heavy right-handed neutrinos that exist in most of the standard model extensions that address dark matter (DM) and neutrino mass at the loop level. In order to probe the collider effect of these LFV interactions, we impose the assumption that the model parameters give the right values of the DM relic density and fulfill the constraints from the LFV processes $\ell_α\rightarrow\ell_βγ$ and $\ell_α\rightarrow3\ell_β$. We also investigate the possibility of probing these interactions, and hence the right-handed neutrino, at leptonic collid…
We employ the low energy Minimal Supersymmetric Standard Model (MSSM) to explore the parameter space associated with $Z$-pole and Higgs-pole solutions. Such parameter spaces can not only saturate the cold dark matter relic density bound within 5$σ$ set by the Planck 2018, but also satisfy the other standard collider mass bounds and B-physics bounds. In particular, we show that the right-handed selectron can be light. Thus, we propose a search for the relatively heavier right-handed selectron at the future lepton colliders with the center-of-mass energy $\sqrt{s}=240$ GeV and integrated luminos…
The decay modes $\bar{B}_s \rightarrow π^0(ρ^0 )\,η^{(')} $ are dominated by electroweak penguins that are small in the standard model. In this work we investigate the contributions to these penguins from a model with an additional $U(1)'$ gauge symmetry and show there effects on the branching ratios of $\bar{B}_s \rightarrow π^0(ρ^0 )\,η^{(')} $. In a scenario of the model, where $Z^\prime$ couplings to the left-handed quarks vanish, we show that the maximum enhancement occurs in the branching ratio of $\bar B^0_s\to \,π^0\,η'$ where it can reach $6$ times the SM prediction. On the other hand…
Lepton flavour violation from right-handed neutrino thresholds
在超对称跷跷板机制下重新评价了带电轻子味破坏。本文指出，右手中微子的非平凡味结构，其影响迄今为止研究较少，可以引起显着的slepton味转变。在中微子Yukawa耦合为O（1）的前提下，右手中微子混合贡献可以构成$μ\rightarrow e γ$振幅的基础，它本身可能导致一个实验上可达到的速率，给出一个典型的低能s粒子谱。重点放在最近测得的轻子混合角$θ_{13}$以及轻子CP破坏相的关键作用。
We show that under current experimental bound of the decays $e_a\rightarrow e_bγ$, the recent experimental data of the muon anomalous magnetic dipole moment $(g-2)_μ$ can be explained in the framework of the 3-3-1 model with right handed neutrinos. In addition, all of these branching ratios can reach closely the recent experimental upper bounds.
Given that the two-Higgs-doublet model of type III (2HDM-III) has the potential to address the $R_{D^{(\ast)}}$ anomalies while the resolution to the $R_{K^{(\ast)}}$ deficits requires new degrees of freedom within this framework, we consider in this paper a unified scenario where the low-scale type-I seesaw mechanism is embedded into the 2HDM-III, so as to accommodate the $R_{D^{(\ast)}}$ and $R_{K^{(\ast)}}$ anomalies as well as the neutrino mass. We first revisit the $R_{D^{(\ast)}}$ anomalies and find that the current world-averaged results can be addressed at $2σ$ level without violating …
We consider scenarios with a heavy $Z^\prime$ gauge boson with flavour non-universal quark and lepton couplings with the goal to illustrate how the cancellation of gauge anomalies generated by the additional U(1)$^\prime$ gauge symmetry would imply correlations between FCNC processes in the quark sector, in the lepton sector and most interestingly between quark flavour and lepton flavour violating processes. We present scenarios with only left-handed flavour-violating $Z^\prime$ couplings and those with also right-handed flavour-violating couplings. These are characterized by a small number of…
We study the nature of the flavor changing neutral couplings of the top quark with the Higgs boson and the up/charm quark in the $t\bar{t}$ production at linear colliders. There are previous bounds on such tqH couplings at both, linear and hadronic colliders, with the assumption that it couples equally to the left and the right handed fermions. In this paper we examine the chirality of the tqH coupling and construct different observables which will be sensitive to it. The kinematics of the emitted q from t $\rightarrow$ qH in $t\bar{t}$ production is discussed and it was found that the polar a…
Diagnosing lepton-nonuniversality in $b \to s \ell \ell$
半轻子B衰变的分支比$(B \to H μμ)$/$(B \to H ee)$ with $H=K, K^*,X_s, K_0(1430), ϕ, \ldots$是轻子普适性的灵敏探针。在标准模型中，基本的味变中性流过程$b\rightarrow s \ell \ell$是轻子味普适的。然而，在弱标度以上具有新的违反物理的味道的模型可以给出实质性的非普适贡献。这种新物理学的主要贡献可以通过涉及左手或右手夸克的有效六维算子来参数化。我们证明了在双比$R_{X_s}/R_K$、$R_{K^*}/R_K$和$R_ϕ/R_K$中，对新物理耦合到左手夸克的依赖被抵消了。因此，对这些双比率中的任何一个的测量都是对味非普适物理与右手夸克耦合的一个干净的探测。我们还指出，观测$R_{X_s}$，$R_{K^*}$，$R_{K_0(1430)}$和$R_ϕ$取决于相同的威尔逊系数的组合，因此满足简单的一致性关系。
We present an $SU(3)^{}_{c}\times SU(2)^{}_{L}\times SU(2)^{}_{R}\times U(1)_{L}^{}\times U(1)_{R}^{}\rightarrow SU(3)^{}_{c}\times SU(2)^{}_{L}\times SU(2)^{}_{R}\times U(1)^{}_{B-L}$ left-right symmetric model with a discrete parity symmetry to realize a universal seesaw scenario. The model can simultaneously solve the strong CP problem without resorting to the unobserved axion and explain the 750 GeV diphoton resonance reported recently by the ATLAS and CMS collaborations at the LHC. Owing to large suppressions in the two-loop induced Dirac mass terms, the Majorana mass matrices of left- an…
The flipped 3-3-1 model discriminates lepton families instead of the quark ones in normal sense, where the left-handed leptons are in two triplets plus one sextet while the left-handed quarks are in antitriplets, under $SU(3)_L$. We investigate a minimal setup of this model and determine novel consequences of dark matter stability, neutrino mass generation, and lepton flavor violation. Indeed, the model conserves a noncommutative $B-L$ symmetry, which prevents the unwanted vacua and interactions and provides the matter parity and dark matter candidates that along with normal matter form gauge …
The electroweak unification group $G\equiv SU(2)_L\times U(1)_e\times U(1)_μ\times U(1)_τ$ in which each fermion multiplet has its own $U(1)$ factor was proposed in 1986 to get the neutrino mass matrix. In this paper, the gauge group G is restricted to lepton section only, leaving quark multiplets as in the standard model. In addition to lepton multiplets $L_e$, $L_μ$ and $L_τ$, there are three $SU(2)$singlet right handed neutrinos $N_{R}^{(i)}$'s. WIth the breaking of G to $SU(2)_L\times U(1)$, the right handed neutrinos acquire heavy Majorana masses. Three heavy right handed neutrinos $N_{R}…
MAJOR 1.5 - A Monte Carlo Generator for Heavy Majorana Neutrinos in $ep$ Collisions
蒙特卡罗发生器{ \sc Major} 1.5模拟了在深度非弹性散射中，重Majorana中微子通过轻子混合或“轻”右手$W$ -玻色子（即$e^{\pm} p \rightarrow {N} X \rightarrow{e}^{\pm} W^{\mp} X$或$ν_e Z X$）交换的产生和衰变。本手册中介绍了物理和编程方面的内容。
As the U(1) extension of the minimal supersymmetric standard model, the $U(1)_X$SSM has new super fields such as right-handed neutrinos and three Higgs singlets. In the $U(1)_X$SSM, the lightest CP-even Higgs mass $m_{h^0}$ is researched through the Higgs effective potential with one loop corrections. We also calculate the Higgs decays $h^0\rightarrowγγ$, $h^0\rightarrow VV~(V=W,~Z)$, $h^0\rightarrow l\bar{l}Z$ and $h^0\rightarrow ν\barνZ$. The obtained results are reasonable, which are in favour of the study of the Higgs characteristic and the phenomenology of the $U(1)_X$SSM.
$U(1)_X$SSM is the extension of the minimal supersymmetric standard model(MSSM) and its local gauge group is $SU(3)_C\times SU(2)_L \times U(1)_Y \times U(1)_X$. To obtain this model, three singlet new Higgs superfields and right-handed neutrinos are added to MSSM. In the framework of $U(1)_X$SSM, we study lepton flavor violating decays $τ\rightarrow{Pl}(P=π,~η,~η^\prime;~l=μ,~e)$. According to the latest experimental data of $τ\rightarrow{Pe}$ and $τ\rightarrow{Pμ}$, the influence of different sensitive parameters on the results is analyzed to make a reasonable prediction for future experimen…
The ground-state (lightest) hybrid nonet with exotic quantum numbers $J^{PC}=1^{-+}$ and the nonet of their chiral partners with $J^{PC}=1^{+-}$ build a homochiral multiplet involving left- and right-handed currents, which under chiral transformation change just as (axial-)vector mesons. Masses and interactions of hybrids can be obtained in the context of the extended Linear Sigma Model. Here, we concentrate on the decays oh hybrids into two pseudoscalar mesons, such as $ηπ$ and $η^{\prime}π$ modes. Indeed, $π_{1}(1400)\rightarrowπη$ and $π_{1}(1600)\rightarrowπη^{\prime}$ have been seen in ex…
Updated Bounds on the Minimal Left-Right Symmetric Model from LHC Dilepton Resonance Searches
International Institute of Physics, Universidade Federal do Rio Grande do Norte（北里奥格兰德联邦大学国际物理研究所）；Departamento de Física, Universidade Federal Rural do Rio de Janeiro（里约热内卢联邦农村大学物理系）；Departamento de Física, Universidade Federal do Rio Grande do Norte（北里奥格兰德联邦大学物理系）；Facultad de Ciencias, Universidad de La Serena（拉塞雷纳大学理学院）；Millennium Institute for Subatomic Physics at High-Energy Frontier (SAPHIR)（高能前沿亚原子物理千年研究所（SAPHIR））；Laboratoire de physique nucléaire et des hautes énergies (LPNHE), Sorbonne Université（索邦大学核物理与高能物理实验室（LPNHE））
To solve the $μ$ problem and generate three tiny neutrino masses in the MSSM, the $μ$ from $ν$ Supersymmetric Standard Model ($μν$SSM) introduces three singlet right-handed neutrino superfields, which lead to the mixing of the Higgs doublets with the sneutrinos. The mixing affects the lightest Higgs boson mass and the Higgs couplings. The present observed 95\% CL upper limit on signal strength of the 125 GeV Higgs boson decay $h\rightarrow Zγ$ is 6.6, which still is plenty of space to prove the existence of new physics. In this work, we investigate the signal strength of the 125 GeV Higgs boso…
By adding new gauge singlets of neutral leptons, the improved versions of the 3-3-1 models with right-handed neutrinos have been recently introduced in order to explain recent experimental neutrino oscillation data through the inverse seesaw mechanism. We prove that these models predict promising signals of lepton-flavor-violating decays of the standard-model-like Higgs boson $h^0_1\rightarrow μτ,eτ$, which are suppressed in the original versions. One-loop contributions to these decay amplitudes are introduced in the unitary gauge. Based on a numerical investigation, we find that the branching…
We consider the SM extension with additional light real singlet scalar, right-handed neutrino and nonrenormalizable Yukawa interaction for the first two generations. We show that the proposed model can explain the observed $(g - 2)$ muon anomaly. Phenomenological consequences as flavour violating decays $τ\rightarrow μμμ, μμe, μe e $ are briefly discussed. We also propose the $U_R(1)$ gauge generalization of the SM with complex scalar singlet and nonzero right-handed charges for the first two generations.
The nonleptonic two-body $Λ_b\rightarrow Λψ$ decays with $ψ=J/ψ$ or $ψ(2S)$ are investigated based on the perturbative QCD approach. These are color-suppressed processes in which the nonfactorizable contributions are confirmed to be dominant. Angular momentum conservation allows us to describe the concerned decays by four independent complex helicity amplitudes. It is observed that the negative-helicity states for the $Λ$ baryon are preferred as expected in the left-handed nature of the charged-current interaction. The obtained results for the helicity amplitudes are used to compute the branch…
We consider a simple extension of the Standard Model with two singlet scalar fields and three heavy right-handed neutrinos. One of the scalar fields serves as an MeV scale dark matter and its stability is ensured by the introduction of an extra $Z_2$ symmetry. The second scalar (which is even under the $Z_2$ symmetry) generates the mass term of the scalar, contributes to the $3 \rightarrow 2$ annihilation process required for the correct relic density of the dark matter and it also contributes to the leptogenesis. The right-handed neutrinos are responsible for the generation of light neutrino …
Vacuum Stability Constraints on the Minimal Singlet TeV Seesaw Model
考虑了在标准模型中加入两个轻子数相反的规范单态右手中微子的最小跷跷板模型。在这个模型中，中微子质量的微小是由一个单态与标准左手中微子之间的微小轻子数破坏耦合来解释的。这使得右手中微子的质量可以达到TeV量级，并且轻态和重态之间可以有明显的混合。这个模型是完全重建的中微子振荡参数除了总的耦合强度。我们表明，整体耦合强度$y_ν$的狄拉克型耦合之间的左手中微子和单态之一，可以限制考虑的（Meta）稳定性界限上的电弱真空。在这种情况下，带电轻子的轻子味破坏衰变可以是可观的，这可以进一步限制$y_ν$，右手中微子在TeV尺度。我们讨论了$y_ν$从过程$μ\rightarrow e γ$和考虑真空（Meta）稳定性的希格斯自耦合的约束，这种情况下的组合约束。我们还简要地讨论了无中微子双β衰变的影响和可能的签名模型，可以预期在对撞机。
