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The smallness of fermion masses and mixing angles has recently been been attributed to approximate global $U(1)$ symmetries, one for each fermion type. The parameters associated with these symmetry breakings are estimated here directly from…

High Energy Physics - Phenomenology · Physics 2009-12-30 Lawrence Hall , Steven Weinberg

We present general one-loop contributions to the decay processes $H\rightarrow f\bar{f}\gamma$ including all possible the exchange of the additional heavy vector gauge bosons, heavy fermions, and charged (also neutral) scalar particles in…

High Energy Physics - Phenomenology · Physics 2022-04-20 Vo Van On , Dzung Tri Tran , Chi Linh Nguyen , Khiem Hong Phan

The observation of lepton flavor violating processes at colliders could be a clear signal of a non-minimal neutrino sector. We define a 5-parameter model with a pair of TeV fermion singlets and arbitrary mixings with the three active…

High Energy Physics - Phenomenology · Physics 2020-04-15 G. Hernández-Tomé , J. I. Illana , G. López Castro , M. Masip , P. Roig

Studies of rare decays of charmed mesons into the final states containing leptons is an important vehicle in low-energy searches for new physics. I review theoretical implications of those studies involving transitions with and without…

High Energy Physics - Phenomenology · Physics 2017-04-13 Alexey A Petrov

In this paper, we present the calculations for $H\rightarrow f\bar{f}\gamma$ in the $U(1)_{B-L}$ extension for Standard Model. Analytic results for one-loop form factors in the decay process are expressed in terms of the scalar one-loop…

High Energy Physics - Phenomenology · Physics 2022-09-29 Khiem Hong Phan , Anh Thu Nguyen , Dzung Tri Tran

We analyze flavor-changing-neutral-current (FCNC) effects in the $b\to s$ transitions that are induced by family non-universal $U(1)'$ gauge symmetries. After systematically developing the necessary formalism, we present a correlated…

High Energy Physics - Phenomenology · Physics 2010-01-06 Vernon Barger , Lisa L. Everett , Jing Jiang , Paul Langacker , Tao Liu , Carlos E. M. Wagner

In a previous work we have showed that the ${\cal Z}_{2}^{\prime}$ Symmetry, imply that the light fermions, the electron and the quarks, $u,d$ and $s$, get their masses only at one loop level. Here, we considere the more general hypothesis…

High Energy Physics - Phenomenology · Physics 2009-01-06 C. M. Maekawa , M. C. Rodriguez

The leptons are viewed as composite objects, exhibiting anomalous magnetic moments and anomalous flavor-changing transition moments. The decay \mu \to e \gamma is expected to occur with a branching ratio of the same order as the present…

High Energy Physics - Phenomenology · Physics 2007-05-23 Xavier Calmet

We have studied lepton flavor violation processes $\mu\to e\gamma$ and $\mu-e$ conversion in nuclei induced by unparticle. Both ${\rm Br}(\mu\to e\gamma)$ and $\mu-e$ conversion rate ${\rm CR}(\mu-e,{\rm Nuclei})$ strongly depend on the…

High Energy Physics - Phenomenology · Physics 2008-11-28 Gui-Jun Ding , Mu-Lin Yan

We address the recent anomalies in semi-leptonic $B$-meson decays using a model of fermion masses based on the $U(2)$ flavor symmetry. The new contributions to $b \to s \ell \ell$ transitions arise due to a tree-level exchange of a…

High Energy Physics - Phenomenology · Physics 2016-01-20 Adam Falkowski , Marco Nardecchia , Robert Ziegler

Lepton flavor-violating processes offer interesting possibilities to probe new physics at multi-TeV scale. We discuss those in the framework of effective field theory, emphasizing the role of gluonic operators. Those operators are obtained…

High Energy Physics - Phenomenology · Physics 2017-08-09 Alexey A. Petrov , Dmitry V. Zhuridov

The dipole moments of the leptons and quarks are matrices in flavor space, which can potentially reveal as much about the flavor structure of the theory as do the mass matrices. The off-diagonal elements of the dipole matrices lead to…

High Energy Physics - Phenomenology · Physics 2014-11-17 K. S. Babu , S. M. Barr , Ilja Dorsner

It is argued that heavy-quarks traversing a Quark Gluon Plasma, undergo a multi-stage modification process, similar to the case of light flavors. Such an approach is applied to heavy-quark energy loss, which includes a rare-scattering,…

Nuclear Theory · Physics 2019-05-22 Shanshan Cao , Abhijit Majumder , Guang-You Qin , Chun Shen

A correlated analysis of observables arising from loop induced effects from a vectorlike generation is given. The observables include flavor changing radiative decays $\mu\to e \gamma, \tau\to \mu \gamma, \tau\to e \gamma$, electric dipole…

High Energy Physics - Phenomenology · Physics 2018-10-17 Amin Aboubrahim , Tarek Ibrahim , Ahmad Itani , Pran Nath

We investigate, in detail, a model in which the third family fermions are subjected to an SU(2) dynamics different from the first two families. Constrained by the precision Z-pole data, the heavy gauge boson mass is bounded from below to be…

High Energy Physics - Phenomenology · Physics 2016-08-25 Ehab Malkawi , C. -P. Yuan

This paper addresses the role of Large Extra Dimensions in some flavor changing neutral current (FCNC) driven processes. In particular we have investigated radiative decays of charged leptons within models with only one universal extra…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ikaros I. Bigi , George Chiladze , Gela Devidze , Christoph Hanhart , Akaki Lipartelian , Ulf-G. Meissner

We address Standard Model predictions for flavor-changing radiative transitions of the pseudoscalar charm mesons. Short-distance contributions in $D$ radiative transitions are contrasted with those in B decays. A full analysis is presented…

High Energy Physics - Phenomenology · Physics 2010-04-06 Gustavo Burdman , Eugene Golowich , JoAnne L. Hewett , Sandip Pakvasa

The rare baryonic decays $\Lambda_b \to \Lambda \mu^+ \mu^-$ and $\Lambda_b \to \Lambda \gamma$ can complement rare $B$ meson decays in constraining models of new physics. In this work, we calculate the relevant $\Lambda_b \to \Lambda$…

High Energy Physics - Lattice · Physics 2012-12-20 William Detmold , C. -J. David Lin , Stefan Meinel , Matthew Wingate

We analyze the flavor changing decay $h\rightarrow \mu \tau $ in the framework of a Two Higgs Doublet Model with a fourth generation of fermions (4G2HDM) which couples only to the heavy scalar doublet. We obtain that the respective…

High Energy Physics - Phenomenology · Physics 2018-04-03 S. Chamorro-Solano , A. Moyotl , M. A. Pérez

We present results for the phase diagram of three flavor QCD for \mu_B ~ 500 MeV. Our simulations are performed with imaginary chemical potential \mu_I for which the fermion determinant is positive. Physical observables are then fitted by…

High Energy Physics - Lattice · Physics 2008-11-26 Ph. de Forcrand , O. Philipsen