Using the effective Lagrangian formalism, the anomalous magnetic and electric dipole moments of the tau-lepton in the $μ^{+}μ^{-} \rightarrow μ^{+}γ^{*} γ^{*} μ^{-}\rightarrow μ^{+}τ\barτμ^{-}$ process at the future muon colliders at the $\sqrt{s}=1.5, 3$ and $6$ TeV are investigated. In addition, the bounds at the $95\%$ confidence level on the dipole moments of the tau-lepton using different integrated luminosities are estimated. It is shown that the $μ^{+}μ^{-} \rightarrow μ^{+}γ^{*} γ^{*} μ^{-}\rightarrow μ^{+}τ\barτμ^{-}$ process leads to a remarkable improvement in the existing experimen…
In this paper the production cross section $pp\rightarrow (γ, Z) \to ν_τ\bar ν_τγ+X$ in $pp$ collisions at $\sqrt{s}=8, 13, 14, 33TeV$ is presented. Furthermore, we estimate bounds at the $95\%C. L.$ on the dipole moments of the tau-neutrino using integrated luminosity of ${\cal L}=20, 50, 100, 200, 500, 1000, 3000 fb^{-1}$ collected with the ATLAS detector at the LHC and we consider systematic uncertainties of $δ_{sys}=0, 5, 10\%$. It is shown that the process under consideration is a good prospect for probing the dipole moments of the tau-neutrino at the LHC.
A novel method for the direct measurement of the elusive magnetic and electric dipole moments of the tau lepton is presented. The experimental approach relies on the production of tau+ leptons from Ds+ -> tau+ nu_tau decays, originated in fixed-target collisions at the LHC. A sample of polarized tau+ leptons is kinematically selected and subsequently channeled in a bent crystal. The magnetic and electric dipole moments of the tau+ lepton are measured by determining the rotation of the spin-polarization vector induced by the intense electromagnetic field between crystal atomic planes. The exper…
We investigate the dipole moments of the tau- neutrino at high-energy and high luminosity at linear electron positron colliders, such as CLIC or ILC through the analysis of the reaction $e^{+}\, e^{-}\rightarrow ν\, \bar ν\,γ$ in the framework of the $SU(4)_L \times U(1)_X$ model. The limits on dipole moment were obtained for integrated luminosity of $\cal{L}$= 500-2000\, fb$^{-1}$ and center of mass between 0.5 and 3.0 TeV. The estimated limits for the tau-neutrino magnetic and electric dipole moments are improved by 2-3 orders of magnitude and complement previous studies on the dipole moment…
In this paper, using the Bestest Little Higgs Model (BLHM) we calculate at the one-loop level the contributions to the Anomalous Magnetic Dipole Moment (AMDM) and Anomalous Weak Magnetic Dipole Moment (AWMDM) of the tau-lepton. The implications from this model are study, emphasizing the contributions of the new physics induced by the new scalar and vector bosons of the BLHM: $S_i=H_0, A_0, ϕ^{0}, η^{0}, σ, H^{\pm}, ϕ^{\pm}, η^{\pm}$, and $V_i=Z', W'$, because these quantify the new physics. With these new contributions we estimated bounds on both the real and imaginary parts of the AMDM and AW…
We conduce a study to probe the sensitivity of the process $e^+e^-\rightarrow (γ, Z) \to ν_τ\bar ν_τγ$ to the total cross section, the magnetic moment and the electric dipole moment of the tau-neutrino in a model-independent way. For this study, the beam polarization facility at the Compact Linear Collider (CLIC) along with the typical center-of-mass energies $\sqrt{s}=380-3000\hspace{0.8mm}GeV$ and integrated luminosities ${\cal L}=10-3000\hspace{0.8mm}fb^{-1}$ is considered. We estimate the sensitivity at the $95\%\hspace{1mm}$ Confidence Level (C.L.) and systematic uncertainties $δ_{sys}=0,…
In the framework of precision experiments, the search for electric dipole moments and the precise determination of magnetic dipole moments (g-2) have since long been of prime interest. Hadronic decays offer the best accuracy, since only the kinematic information carried by a single neutrino per decay is lost. Thus, they reveal more easily precious information on the helicity of the initial tau lepton. However, in contrast to one- or two-body hadronic final states, the description of hadronic multi-body final states depends on the model for the hadronic current. In this work, we determine how t…
In this paper we discuss the possibility of measuring the anomalous magnetic and electric dipole moments of the $τ$ lepton. The method consists in studying the spin precession induced by the strong effective magnetic field inside channels of a bent crystal with a dedicated setup at the CERN Large Hadron Collider.
In this work we study the sensitivity on the anomalous magnetic and electric dipole moments of the tau-neutrino in the framework of the $SU(2)_L\times U(1)_Y\times U(1)_{B-L}$ electroweak model at future $e^+e^-$ linear colliders as the ILC and CLIC. For our study we consider the process $e^{+}e^{-}\rightarrow ( Z, Z', γ) \to ν_τ\bar ν_τγ$. For center-of-mass energies of $\sqrt{s}=1000-3000\hspace{0.8mm}GeV$ and integrated luminosities of ${\cal L}=500-2000\hspace{0.8mm}fb^{-1}$, we derive $95 \% \hspace{1mm}$ C.L. limits on the dipole moments $|μ_{ν_τ}(μ_B)| \leq 6.28 \times 10^{-9}$ and $|d_…
Spin effects in the tau-lepton pair induced by anomalous magnetic and electric dipole moments
NSC Kharkiv Institute of Physics and Technology(哈尔科夫物理与技术国立科学中心);V. N. Karazin Kharkiv National University(瓦西里·卡扎金哈尔科夫国立大学);M. Smoluchowski Institute of Physics, Jagiellonian University(雅盖隆大学M.斯莫卢霍夫斯基物理研究所)
Pair production of tau leptons in two photon collision ${γγ\to τ^{+}τ}^{-}$ is studied at CLIC to test CP violating QED couplings of tau leptons. CP violating effects are investigated using tau pair spin correlations which are observed through the hadronic decay of each $τ$ into $πν$. Competitive bounds with previous works on the electric dipole moment from CP odd terms have been obtained.
Precise measurement of the Electric Dipole Moment (EDM) and anomalous magnetic moment ($g$-2) of particles are important tests of Beyond Standard Model (BSM) physics. It is generally believed that the tau lepton couples more strongly to BSM due to its large mass, and can be searched for at collider experiments. A new method to approximately reconstruct the neutrinos from the hadronic decays of $τ^-τ^+$ pairs produced at $e^-e^+$ tau factories is proposed. With all final state particle momenta available, observables based on matrix elements and sensitive to BSM are calculated. It is estimated t…
Models for the Electric Dipole Moment and Anomalous Magnetic Moment of the Tau Lepton
Tsung-Dao Lee Institute, Shanghai Jiao Tong University(上海交大凌波书院);School of Physics and Astronomy, Shanghai Jiao Tong University(上海交通大学物理与天文学院);School of Physics, Henan Normal University(河南师范大学物理学院)
Linearly Polarized Photon Fusion as a Precision Probe of the Tau Lepton Dipole Moments at Lepton Colliders
Fudan University(复旦大学);Peking University(北京大学);Institute of High Energy Physics, Chinese Academy of Sciences(中国科学院高能物理研究所);Hangzhou Normal University(杭州师范大学)
We establish model independent bounds on the anomalous magnetic and electric dipole moments of the tau-lepton using the two-photon processes $γγ\to τ^+τ^-$ and $γγ\to τ^+τ^-γ$. We use ${\cal L}=10, 50, 100, 300, 500, 1000, 1500, 2000, 3000 \hspace{0.8mm}fb^{-1}$ of data collected with the future $e^+e^-$ linear collider such as the CLIC at $\sqrt{s}=380, 1500, 3000 \hspace{0.8mm}GeV$ and we consider systematic uncertainties of $δ_{sys}=0, 3, 5\hspace{1mm}\%$. Precise bounds at $95\%$ C. L. on the anomalous dipole moments to the tau-lepton $-0.00015\leq \tilde{a}_τ\leq 0.00017$ and $|\tilde{d}_…
About possibility to measure an electric dipole moment (EDM) of nuclei in the range $10^{-27} ÷10^{-32}$ $e \cdot cm$ in experiments for search of time-reversal violating generation of magnetic and electric fields
We have examined the anomalous electromagnetic moments of the tau lepton in the processes $e^{-}γ\to ν_eτ\barν_τ$ ($γ$ is the Compton backscattering photon) and $e^{-}e^{+} \to e^{-}γ^* e^{+} \to ν_{e}τ\barν_τe^+$ ($γ^*$ is the Weizsacker-Williams photon) with unpolarized and polarized electron beams at the CLIC. We have obtained 95$\%$ confidence level bounds on the anomalous magnetic and electric dipole moments for various values of the integrated luminosity and center-of-mass energy. Improved constraints of the anomalous magnetic and electric dipole moments have been obtained compared to th…
Bounds On Anomalous Magnetic And Electric Moments Of Tau Lepton From LEP And Lepton Flavor Violation
τ轻子的反常磁偶极矩和电偶极矩的最严格的界限是由埃斯克里巴诺和马索[6]从LEP的Z宽度在一个有效的拉格朗日新物理方法中推导出来的。本文指出,Escribano和Massó引入的高维算符不仅将τ轻子的中性流修改为Z规范玻色子和光子,而且诱导轻子味破坏(LFV)。LFV效应的大小主要取决于轻子质量产生的动力学。假设轻子质量矩阵为Fritzsch反序形式,指出$μ\to e γ$的实验极限将把τ轻子的反常磁矩和电偶极矩分别推到$10^{-11}$和$10^{-25} e cm$.
Learning about flavour structure from tau to ell gamma and mu to e gamma?
目前和即将进行的实验应该可以将辐射轻子衰变的灵敏度提高一个数量级。本文假设τ->(e,μ)γ衰变之一被观察到,并探讨了所需的新的风味耦合的结构和后果。在简单的模型(一个低尺度的跷跷板,leptoquarks),它示出的偶极顶点函数是成比例的产品的风味矩阵从拉格朗日(一个“Jarlskog样”不变),只要环粒子弱耦合到希格斯玻色子。其次,如果偶极顶点函数具有分层结构,则这可能意味着由于mu --> e gamma上的界限所暗示的“近似零”,因此只能观察到一些tau -->(e,mu)gamma模式。这种潜在的测试的层次结构的假设进行了讨论。
Search For Non-Standard Model CP/T violation At Tau-Charm Factory
我们系统地调查发现CP/T违反的可能性,在$τ$部门在陶魅力工厂。CP/T破坏可能发生在$τ$对产生过程中,表示为电偶极矩,并在$tau$衰减过程中。假设在Tau Charm工厂可以观测到$10^{-19}$ e cm的电偶极矩和$10^{-3}$的CP/T破坏效应,我们研究了与产生$τ$扇区CP/T破坏有关的SM的所有可能扩展。并指出有几种模型有望产生这种CP/T破坏。对于这些模型,我们考虑了所有的理论和目前的实验约束,并发现存在一些参数空间,这将导致一个可测量的CP/T破坏。因此,我们认为Tau Charm工厂是发现$τ$扇区CP/T违反的一个有希望的地方。
We consider renormalizable couplings of neutral $ϕ$, singly $ϕ^\pm$, and doubly charged $ϕ^{\pm\pm}$ scalar bosons to leptons and the $Z$ gauge boson and calculate the one-loop contributions to the anomalous weak magnetic dipole moment (AWMDM) $a_τ^W$ and the weak electric dipole moment (WEDM) $d_τ^W$ of a charged lepton in a model independent way. The analytic expressions are presented in terms of both parametric integrals and Passarino-Veltman scalar functions. Among the new contributions, there are those arising from the vertices of the type $ϕ^\pm W^\mp Z$ and $Z ϕ_iϕ_j$ ($i\ne j$), along …