With U-spin symmetry, b->s and b->d penguin decays could be a subtle probe of CP violating new physics contributions. We show that, for B->PP (P stands for a pseudoscalar meson), the U-spin relation is expected to be violated for only one decay pair by assuming that new physics affects only b->s transition processes. We also very shortly discuss the polarizations of two types of U-spin pairs for B->VV (V stands for a vector meson).
Filtering glueball from $q\bar{q}$ production in proton proton or double tagged $e^+e^- \to e^+e^-R$ and implications for the spin structure of the Pomeron
Numerous exotic candidates containing a heavy quark and anti-quark (the so-called $XYZ$ states) have been reported since the observation of the $X(3872)$ in 2003. For these systems a study of the implications of the heavy quark spin symmetry and its breaking is expected to provide useful guidance towards a better understanding of their nature. For instance, since the formation of the complete spin multiplets is described with the same parameter sets, in some cases the currently available experimental data on the $XYZ$ states allows us to predict properties of spin partner states. To illustrate…
The B -> pi pi, pi K Puzzles: Implications for Hadron Physics, New Physics and Rare Decays
B介子系统是探索强相互作用、标准模型的夸克味部分和寻找新物理的有趣探针。在这个计划中，非轻子B衰变，从QCD的角度来看特别具有挑战性，起着关键作用。在讨论了处理四夸克算符对应的强子矩阵元的策略和新物理在B衰变中表现出来的流行途径之后，我们专注于B -> pi pi，pi K衰变的B工厂数据中令人困惑的模式;我们探索了它们对强子物理，新物理和罕见的K和B衰变的影响。
Precise determination of top-quark pairs is an essential tool for understanding the overall consistency of the standard model (SM) expectations, understanding limited New Physics (NP) models, through spin-spin correlation and polarization parameters, and has a critical impact on the analyses strategies at upcoming LHC programs. In this work, we review and discuss various state-of-the-art Monte Carlo (MC) methodologies as \textsc{MadGraph5}\_aMC@NLO, \textsc{Sherpa}, \textsc{Powheg-Box} and \textsc{Pythia8}, which are Matrix Element (ME)$/$Parton Shower (PS) matching generators including a comp…
I show that breaking $B-L$ by one unit of this charge is suitable for neutrino mass generation through an inverse seesaw mechanism, stabilizing a dark matter candidate without supersymmetry, as well as solving the muon anomalous magnetic moment and the $W$ mass deviation via dark field contributions. The new physics is governed by the residual $Z_3$ symmetry of $B-L$ isomorphic to the center of the color group, instead of the well-studied matter parity.
Future precision measurements of the Standard Model (SM) parameters at the proposed Z-factories and Higgs factories may have significant impacts on new physics beyond the Standard Model (BSM). We illustrate this by focusing on the Type-II two Higgs doublet model. A multi-variable global fitting is performed with full one loop contributions to relevant couplings. The Higgs signal strength measurements at proposed Higgs factories can provide strong constraints on new physics and are found to be complementary to the Z-pole measurements.
Prompted by the recent Dresden-II reactor data we examine its implications for the determination of the weak mixing angle, paying attention to the effect of the quenching function. We also determine the resulting constraints on the unitarity of the neutrino mixing matrix, as well as on the most general type of nonstandard neutral-current neutrino interactions.
Quantum gravity places important consistency conditions on low-energy effective field theory, such as the absence of global symmetries. These may have important consequences in the search for particle physics beyond the Standard Model. We review some of these conditions and their phenomenological implications for the strong CP problem, the weak scale, new gauge interactions, and cosmology. We also offer some general comments on how these ideas can guide model building.
I discuss recent progress on fits to dimension-six operators in the Standard Model Effective Theory (SMEFT). I focus on the top quark sector of the SMEFT, as well as the theoretical advances made in computing SMEFT effects through to next-to-leading order in QCD and the use of these calculations in global fits. I also discuss fits performed to the Higgs and electroweak sectors of the SMEFT and the possibility for performing global fits to multiple sectors simultaneously.
We review aspects of the interplay of asymptotically safe gravity with matter, focusing on the potential predictive power of the quantum scale-symmetry underlying the asymptotically safe fixed point. We explain how an asymptotically safe fixed point for the Standard Model, induced by quantum-gravity fluctuations, might i) render the Standard Model ultraviolet complete and ii) allow us to calculate the values of some of the Standard-Model couplings. In particular, we highlight that such a fixed point might explain the mass-difference between the top and bottom quark.
