Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userDouble Flavor Violating Top Quark Decays in Effective Theories
237
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The possibility of detecting double flavor violating top quark transitions $t to u_itau mu$ ($u_i=u,c$) is explored in a model--independent manner, using the effective Lagrangian approach. Low--energy data, on high precision measurements, and current experimental limits are used to constraint the $tu_iH$ and $Htau mu$ vertices and then to calculate the branching ratio BR$(t to u_itau mu)$. If in the Standard Model BR$(t to u_itau mu)$ is of the order of $10^{-13}$$-10^{-14}$, higgs--mediated double flavor violating top quark decays can occur with branching ratios ranging from $10^{-3}$ to $10^{-4}$ for 114.4 GeV$/c^2$ $< m_H<$ $2m_W$, that is at the reach of the CERN Large Hadron Collider.
rate research
Read More
We propose a novel strategy to test lepton flavor universality (LFU) in top decays, applicable to top pair production at colliders. Our proposal exploits information in kinematic distributions and mostly hinges on data-driven techniques, thus having very little dependence on our theoretical understanding of top pair production. Based on simplified models accommodating recent hints of LFU violation in charged current B meson decays, we show that existing LHC measurements already provide non-trivial information on the flavor structure and the mass scale of such new physics (NP). We also project that the measurements of LFU in top decays at the high-luminosity LHC could reach a precision at the percent level or below, improving the sensitivity to LFU violating NP in the top sector by more than an order of magnitude compared to existing approaches.
We study new top flavor violating resonances that are singly produced in association with a top at the LHC. Such top flavor violating states could be responsible for the Tevatron top forward-backward asymmetry. Since top flavor violating states can directly decay to a top (or anti-top) and jet, and are produced in conjunction with another (oppositely charged) top, the direct signature of such states is a t j (or tbar j) resonance in t tbar j events. In general, these states can be very light and have O(1) couplings to the top sector so that they are copiously produced. We present a search strategy and estimate the discovery potential at the early LHC by implementing the strategy on simulated data. For example, with 1 fb^-1 at 7 TeV, we estimate that a W coupling to d_R tbar_R can be constrained at the 3 sigma level for g_R = 1 and m_W = 200 GeV, weakening to g_R = 1.75 for m_W = 600 GeV. With the search we advocate here, a bound at a similar level could be obtained for top flavor violating Zs, as well as triplet and sextet diquarks.
The size of the branching ratios for the $tau to mu gamma$ and $tau to mu gamma gamma$ decays induced by a lepton flavor violating Higgs interaction $Htau mu$ is studied in the frame of effective field theories. The best constraint on the $Htau mu$ vertex, derived from the know measurement on the muon anomalous magnetic moment, is used to impose the upper bounds $Br(tau to mu gamma)<2.5times 10^{-10}$ and $Br(tau to mu gamma gamma)<2.3times 10^{-12}$, which are more stringent than current experimental limits on this class of transitions.
Exotic Higgs decays are promising channels to discover new physics in the near future. We present a simple model with a new light scalar that couples to the Standard Model through a charged lepton-flavor violating interaction. This can yield exciting new signatures, such as $h to e^+ e^+ mu^-mu^-$, that currently have no dedicated searches at the Large Hadron Collider. We discuss this model in detail, assess sensitivity from flavor constraints, explore current constraints from existing multi-lepton searches, and construct a new search strategy to optimally target these exotic, lepton-flavor violating Higgs decays.
The scalar partner of the top quark (the stop) is relatively light in many models of supersymmetry breaking. We study the production of stops at the Large Hadron Collider (LHC) and their subsequent decays through baryon-number violating couplings such that the final state contains no leptons. A detailed analysis performed using detector level observables demonstrate that stop masses upto $sim 600 gev$ may be explored at the LHC depending on the branching ratios for such decays and the integrated luminosity available. Extended to other analogous scenarios, the analysis will, generically, probe even larger masses.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
