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We speculate about the possible interpretations of the recently observed excess in the $h \to \tau \mu$ decay. We derive a robust lower bound on the Higgs boson coupling strength to a tau and a muon, even in presence of the most general new…

High Energy Physics - Phenomenology · Physics 2015-09-16 Nejc Košnik

We study the semileptonic decays B -> Xs e+ e-, B -> Xs mu+ mu- in generic supersymmetric extensions of the Standard Model. SUSY effects are parameterized using the mass insertion approximation formalism and differences with MSSM results…

High Energy Physics - Phenomenology · Physics 2007-05-23 E. Lunghi

In the light of recent data, we study the new physics effects in the exclusive $b \to s \ell^+\ell^-$ decays from a model independent perspective. Different combinations of the dimension six effective operators along with their respective…

High Energy Physics - Phenomenology · Physics 2020-03-25 Srimoy Bhattacharya , Aritra Biswas , Soumitra Nandi , Sunando Kumar Patra

Within a chiral $SU(15)$ gauge theory in which the Standard Model fermions are bound states of massless preons, we show that proton-decay operators are likely induced at the compositeness scale, $\Lambda_{\rm pre}$. Our estimate of the…

High Energy Physics - Phenomenology · Physics 2023-01-18 Benoît Assi , Bogdan A. Dobrescu

This talk concerns some theoretical patterns of the helicity amplitudes for t --> W b decay. The patterns involve both the standard model's four decay helicity amplitudes, A_{SM}, and also the amplitudes A_{+} in the case of an additional…

High Energy Physics - Phenomenology · Physics 2007-05-23 Charles A. Nelson

We derive the the effective lagrangian that describes the interactions among vector, axial-vector mesons and pseudoscalars starting from the extended chiral quark model (ECQM). The results for the low-energy constants of this effective…

High Energy Physics - Phenomenology · Physics 2008-11-26 Giancarlo D'Ambrosio , Domenec Espriu

We study the effect of the diagonal extended technicolor(ETC) gauge boson on the oblique correction parameters. It is shown that in the $T$ parameter is unacceptably large when the $Zbb$ vertex correction and $S$ parameter are consistent…

High Energy Physics - Phenomenology · Physics 2009-10-28 Tadashi Yoshikawa

The latest standard model predictions of rare leptonic B_q --> l^+ l^- decays are reviewed including recent results of next-to-leading electroweak and next-to-next-to-leading QCD corrections.

High Energy Physics - Phenomenology · Physics 2014-05-21 Christoph Bobeth

Extensions of the Standard Model that include vector-like quarks commonly also include additional particles that may mediate new production or decay modes. Using as example the minimal linear $\sigma$ model, that reduces to the minimal…

High Energy Physics - Phenomenology · Physics 2020-02-19 J. A. Aguilar-Saavedra , J. Alonso-Gonzalez , L. Merlo , J. M. No

The importance of rare $K$ decays especially in the context of a kaon unitarity triangle (KUT) is emphasized. The decay $K_L \to \pi^0 \nu \bar \nu$ is theoretically very clean but experimentally extremely challenging. The Standard Model…

High Energy Physics - Phenomenology · Physics 2023-12-12 Stefan Schacht , Amarjit Soni

We present a concise review of the theoretical status of the rare semileptonic B -> X_s l^+ l^- decays in the standard model. Particular attention is thereby devoted to the recent theoretical progress concerning, on the one hand the…

High Energy Physics - Phenomenology · Physics 2007-05-23 U. Haisch

Electroweak measurements place significant bounds on higher-dimensional versions of the standard model in which the gauge and Higgs fields have Kaluza-Klein excitations. These bounds may be altered quantitatively if chiral matter is also…

High Energy Physics - Phenomenology · Physics 2009-10-31 Christopher D. Carone

Some recent theoretical work on inclusive B decays relevant for the model independent determination of |V_{ub}| and |V_{cb}| is summarized. The theoretical predictions and their reliability for several differential decay distributions in B…

High Energy Physics - Phenomenology · Physics 2007-05-23 Zoltan Ligeti

We calculate the contributions to the rare B-decays, $B \to X_{s,d} \nu \bar \nu$, $B_{s,d} \to l^+l^- $ from the unit-charged technipions. Within the considered parameter space we find that: (a) the enhancements to the branching ratios in…

High Energy Physics - Phenomenology · Physics 2015-06-25 Xiao Zhenjun , Lü Linxia , Guo Hongkai , Lu Gongru

This study examines the rare decay $B \to K_0^*(1430)\,\ell^+ \ell^-$ as a possible probe for new physics beyond the standard model (SM). We first analyze this channel within the SM and then include scalar leptoquark (LQ) contributions. We…

High Energy Physics - Phenomenology · Physics 2026-02-09 M. Dadashzadeh , K. Azizi

We analyse a minimal supersymmetric standard model (MSSM) taking a minimal flavour violation (MFV) structure at the GUT scale. We evaluate the parameters at the electroweak scale taking into account the full flavour structure in the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Enrico Lunghi , Werner Porod , Oscar Vives

We examine the rare decays $B_s\to l^+l^-$ and $B\to Kl^+l^-$ in the framework of the topcolor-assisted technicolor ($TC2$) model. The contributions of the new particles predicted by this model to these rare decay processes are evaluated.…

High Energy Physics - Phenomenology · Physics 2014-11-18 Wei Liu , Chong-Xing Yue , Hui-Di Yang

We present an analysis of the rare exclusive $B$ decays $B\to K\nu\bar\nu$ and $B\to K^{*}\nu\bar\nu$ within the Standard Model (SM), in a model-independent manner, and in a number of new physics (NP) models. Combining new form factor…

High Energy Physics - Phenomenology · Physics 2014-12-17 Andrzej J. Buras , Jennifer Girrbach-Noe , Christoph Niehoff , David M. Straub

We consider the constraints that critical dynamics places on models with a top quark condensate or strong extended technicolor (ETC). These models require that chiral-symmetry-breaking dynamics at a high energy scale plays a significant…

High Energy Physics - Phenomenology · Physics 2009-10-22 R. Sekhar Chivukula , Mitchell Golden , Elizabeth H. Simmons

We estimate the correction to the Zbb-bar vertex arising from the exchanges of the sideways extended technicolor (ETC) boson and the flavor-diagonal ETC boson in the multiscale walking technicolor model. The obtained result is too large to…

High Energy Physics - Phenomenology · Physics 2008-11-26 Chong-Xing Yue , Yu-Ping Kuang , Gong-Ru Lu