Search results for "FLAVOUR"
showing 10 items of 310 documents
Signatures of bosonic squark decays in non-minimally flavour-violating supersymmetry
2010
We investigate couplings of squarks to gauge and Higgs-bosons within the framework of non-minimal flavour violation in the Minimal Supersymmetric Standard Model. Introducing non-diagonal elements in the mass matrices of squarks, we first study their impact on the self-energies and physical mass eigenvalues of squarks. We then present an extensive analysis of bosonic squark decays for variations of the flavour-violating parameters around the two benchmark scenarios SPS1a' and SPS1b. Signatures, that would be characteristic for a non-minimal flavour structure in the squark sector, can be found in wide regions of the parameter space.
Flavor Physics in SUSY Grand Unified Theories
2007
Within Supersymmetric Grand Unified theories with soft breaking terms arising at the Planck scale, it is generally possible to link Flavor Changing Neutral Current (FCNC) and CP violating processes occurring in the leptonic and hadronic sectors. So, a correlated analysis of low-energy observables in the leptonic and hadronic sectors, can provide indications of the existence of a Grand Unified theory at high energies. We show how bounds on leptonic FCNC involving the third generation translate into constraints on FCNC B decays. Moreover, we show that, besides FCNC transitions, also lepton-flavor (LF) universality tests in M l 2 decays (with M = π , K , B ), offer a unique opportunity to stud…
Charged-Higgs phenomenology in the aligned two-Higgs-doublet model
2010
The alignment in flavour space of the Yukawa matrices of a general two-Higgs-doublet model results in the absence of tree-level flavour-changing neutral currents. In addition to the usual fermion masses and mixings, the aligned Yukawa structure only contains three complex parameters zeta(f), which are potential new sources of CP violation [1]. For particular values of these three parameters all known specific implementations of the model based on discrete Z(2) symmetries are recovered. One of the most distinctive features of the two-Higgs-doublet model is the presence of a charged scalar H-+/-. In this work, we discuss its main phenomenological consequences in flavour-changing processes at …
The η′ meson at the physical point with Nf = 2 Wilson twisted mass fermions
2018
We present results for the η′ meson and the topological susceptibility in Nf = 2 flavour lattice QCD. The results are obtained using Wilson twisted mass fermions at maximal twist with pion masses ranging from 340 MeV down to the physical point. A comparison to literature values is performed giving a handle on discretisation effects.
Where we are onθ13: addendum to ‘Global neutrino data and recent reactor fluxes: status of three-flavor oscillation parameters’
2011
In this addendum to arXiv:1103.0734 we consider the recent results from long-baseline $\nu_\mu\to\nu_e$ searches at the T2K and MINOS experiments and investigate their implications for the mixing angle $\theta_{13}$ and the leptonic Dirac CP phase $\delta$. By combining the $2.5\sigma$ indication for a non-zero value of $\theta_{13}$ coming from T2K data with global neutrino oscillation data we obtain a significance for $\theta_{13} > 0$ of about $3\sigma$ with best fit points $\sin^2\theta_{13} = 0.013(0.016)$ for normal (inverted) neutrino mass ordering. These results depend somewhat on assumptions concerning the analysis of reactor neutrino data.
NN Interaction in Chiral Constituent Quark Models
2003
We review the actual state in the description of the nucleon-nucleon (NN) interaction by means of chiral constituent quark models. We present a series of relevant features that are nicely explained within the quark model framework.
The Demise of Flavour Tagging and its Delta-T Dependence
2007
In this work we discuss how the loss of particle-antiparticle identity due to CPT violation affects the observables in the decay of two neutral EPR-correlated $B$-mesons. We study this possible new effect in the context of equal-sign flavour specific decays and we find a considerable modification in the $\Delta t$-dependence of the equal-sign dilepton charge asymmetry, $A_{sl}$. Although the more important changes occur right outside the $\Dt$ region that has been up-to-the-date effectively explored, we show that a deeper experimental research may be able to distinguish a possible existence of this new CPT violating parameter, $\w$. In any case, using the available data for $A_{sl}$, we put…
Theoretical overview of kaon decays
2014
Kaon decays are an important testing ground of the electroweak flavour theory. They can provide new signals of CP violation and, perhaps, a window into physics beyond the Standard Model. At the same time, they exhibit an interesting interplay of long-distance QCD effects in flavour-changing transitions. A brief overview is presented, focusing on a few selected topics of particular interest. A more detailed and comprehensive review can be found in arXiv:1107.6001.
mb at MZ
1998
Abstract The value of the b quark mass at the M Z scale defined in the MS renormalization scheme, m b ( M Z ), was determined using 2.8 million hadronic Z decays collected during 1992-1994 by the DELPHI detector to be m b (M Z )=2.67±0.25 ( stat. )±0.34 ( frag. )±0.27 ( theo. ) GeV/c 2 . The analysis considers NLO corrections to the three-jet production rate including mass effects, and the result obtained agrees with the QCD prediction of having a running b quark mass at an energy scale equal to M Z . This is the first time that such a measurement is performed far above the b b production threshold. The study also verifies the flavour independence of the strong coupling constant for b and l…
Constraining multi-Higgs flavour models
2014
To study a flavour model with a non-minimal Higgs sector one must first define the symmetries of the fields; then identify what types of vacua exist and how they may break the symmetries; and finally determine whether the remnant symmetries are compatible with the experimental data. Here we address all these issues in the context of flavour models with any number of Higgs doublets. We stress the importance of analysing the Higgs vacuum expectation values that are pseudo-invariant under the generators of all subgroups. It is shown that the only way of obtaining a physical CKM mixing matrix and, simultaneously, non-degenerate and non-zero quark masses is requiring the vacuum expectation value…