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We consider supersymmetric extensions of the standard model with general non-universal soft breaking terms. We analyse in a model-independent way the constraints on these terms at the electroweak energy scale coming from gluino mediated…

High Energy Physics - Phenomenology · Physics 2009-10-28 E. Gabrielli , A. Masiero , L. Silvestrini

Investigation of conservation/violation of CP symmetry in the leptonic sector is very essential in understanding the evolution of the universe. Lorentz invariance and CPT are fundamental symmetries of nature. The violation of Lorentz…

High Energy Physics - Phenomenology · Physics 2023-09-25 Supriya Pan , Kaustav Chakraborty , Srubabati Goswami

The issue of Lorentz fine-tuning in effective theories containing higher-order operators is studied. To this end, we focus on the Myers-Pospelov extension of QED with dimension-five operators in the photon sector and standard fermions. We…

High Energy Physics - Phenomenology · Physics 2015-05-18 Carlos M. Reyes , Sebastian Ossandon , Camilo Reyes

We consider the approximate U(2)^3 flavour symmetry exhibited by the quark sector of the Standard Model and all its possible breaking terms appearing in the quark Yukawa couplings. Taking an Effective Field Theory point of view, we…

High Energy Physics - Phenomenology · Physics 2015-06-05 Riccardo Barbieri , Dario Buttazzo , Filippo Sala , David M. Straub

We show that in the minimal 3-3-1 model the flavor changing neutral currents (FCNCs) do not impose necessarily strong constraints on the mass of the $Z^\prime$ of the model if we also consider the neutral scalar contributions to such…

High Energy Physics - Phenomenology · Physics 2013-12-12 A. C. B. Machado , J. C. Montero , V. Pleitez

The influence of Lorentz- and CPT-violating terms of the extended Standard Model on a semi-classical two-level system is analyzed. It is shown that the Lorentz-violating background (when coupled with the fermion sector in a vector way) is…

High Energy Physics - Theory · Physics 2008-11-26 Manoel M. Ferreira , Adalto R. Gomes , Rafael C. C. Lopes

It is pointed out that in a general class of flavour models one can identify certain universally present FCNC operators, induced by the exchange of heavy flavour messengers. Their coefficients depend on the rotation angles that connect…

High Energy Physics - Phenomenology · Physics 2015-07-23 Lorenzo Calibbi , Zygmunt Lalak , Stefan Pokorski , Robert Ziegler

We consider the leptonic and semileptonic (SL) lepton flavour violating (LFV) decays of the charged leptons in the minimal supersymmetric standard model (MSSM). The formalism for evaluation of branching fractions for the SL LFV…

High Energy Physics - Phenomenology · Physics 2008-11-26 Takeshi Fukuyama , Amon Ilakovac , Tatsuru Kikuchi

The theoretical description of fermions in the presence of Lorentz and CPT violation is developed. We classify all Lorentz- and CPT-violating and invariant terms in the quadratic Lagrange density for a Dirac fermion, including operators of…

High Energy Physics - Phenomenology · Physics 2015-06-17 Alan Kostelecky , Matthew Mewes

We argue that lepton flavor violating (LFV) decays $M \to \ell_1 \overline{\ell}_2$ of meson states $M$ with different quantum numbers could be used to put constraints on the Wilson coefficients of effective operators describing LFV…

High Energy Physics - Phenomenology · Physics 2017-10-03 Derek E. Hazard

I discuss a ``more minimal'' modification of the minimal supersymmetric standard model, in which supersymmetry breaking is connected with the physics of flavor. Flavor Changing Neutral Currents (FCNC) for the first two families are…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ann E. Nelson

We investigate a framework of the Minimal Supersymmetric Standard Model (MSSM) in which the quark and lepton flavor structure and suppression of flavor-changing neutral currents (FCNCs) are governed by non-invertible selection rules. By…

High Energy Physics - Phenomenology · Physics 2025-12-29 Yuichiro Nakai , Hajime Otsuka , Yoshihiro Shigekami , Zhihao Zhang

In the context of Supersymmetric Grand Unified theories with soft breaking terms arising at the Planck scale, it is generally possible to link flavor changing neutral current and CP violating processes occurring in the leptonic and hadronic…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. Ciuchini , A. Masiero , L. Silvestrini , S. K. Vempati , O. Vives

These proceedings review the status of present and future bounds on muonic lepton flavour violating transitions in the context of an effective-field theory defined below the electroweak scale. A specific focus is set on the phenomenology of…

High Energy Physics - Phenomenology · Physics 2018-07-02 Giovanni Marco Pruna

A peculiar aspect of the MSSM, the simplest supersymmetric extension of the Standard Model, is that it is usually defined including an ad hoc symmetry, R-parity, whose sole purpose is to forbid rapid proton decay. This symmetry deeply…

High Energy Physics - Phenomenology · Physics 2008-10-16 Christopher Smith

Flavor changing neutral current (FCNC) interactions for a top quark $t$ decays into $Xq$ with $X$ represents a neutral gauge or Higgs boson, and $q$ a up- or charm-quark are highly suppressed in the Standard Model (SM) due to the…

High Energy Physics - Phenomenology · Physics 2018-03-14 P. Q. Hung , Yu-Xiang Lin , Chrisna Setyo Nugroho , Tzu-Chiang Yuan

An effective model for QED with the addition of a nonminimal coupling with a chiral character is investigated. This term, which is proportional to a fixed 4-vector $b_\mu$, violates Lorentz symmetry and may originate a CPT-even Lorentz…

High Energy Physics - Theory · Physics 2012-10-05 A. P. Baeta Scarpelli

We consider neutrino oscillations in the minimal Standard-Model Extension describing general Lorentz and CPT violation. Among the models without neutrino mass differences is one with two degrees of freedom that reproduces most major…

High Energy Physics - Phenomenology · Physics 2009-07-09 Alan Kostelecky , Matthew Mewes

Many extensions of the Standard Model(SM) generate contributions to Flavor Changing Neutral Current(FCNC) processes that must have sufficient flavor suppression to be consistent with experiments, if the new physics (NP) is associated with a…

High Energy Physics - Phenomenology · Physics 2008-12-18 Alakabha Datta

Various ambiguous results on radiatively induced Lorentz and CPT violation in quantum electrodynamics with a modified fermionic sector are reviewed and possible explanations for this ambiguity appearing in the literature are commentated.…

High Energy Physics - Theory · Physics 2009-11-07 W. F. Chen