We investigate to what extent the recently measured value for a non-vanishing direct CP asymmetry in D0 -> K+ K- and D0 -> pi+ pi- decays can be accommodated in the Standard Model (SM) or extensions with a constrained flavour sector, for instance from a sequential 4th generation of quarks (4G). From the comparison with D0 -> K- pi+ branching ratios, we establish large U-spin symmetry (d <-> s) breaking effects with large strong phases between different interfering amplitudes. On the basis of conservative estimates on amplitude ratios - which are supported by an analysis of the breaking of a (c <-> u) symmetry in non-leptonic B0 decays - we find that, in the SM, direct CP asymmetries in the pi+ pi- or K+ K- modes (or in their difference) of the order of several per mille are still plausible. Due to the constraints on the new CP phases in the 4G model, only moderate effects compared to the SM estimates are possible. We suggest CP studies at LHCb as well as at (Super)B-factories of several distinctive modes, such as D+ -> Kbar(*)0 pi+, phi pi+ and Ds -> K(*)0 pi+, phi pi+ (K+) etc., which should shed more light on the short- and long-distance issues underlying CP violation in non-leptonic D-meson decays.
Is charged lepton flavour violation a high energy phenomenon?
对诸如μ-> e γ等罕见过程的研究，严格限制了许多超越标准模型的物理场景中预期的轻子味违反。这通常排除了在高能对撞机（如LHC）上观察到的味道违背。我们在这里讨论的情况下，右手中微子产生通过Z'门户，但只能通过小味违反耦合衰变。因此，工艺速率不受小耦合的抑制，并且尽管μ-> e γ速率小得无法观察，但可以是可见的。
Electric dipole moments from flavoured CP violation in SUSY
所谓的超对称味和CP问题与味的起源有很深的关系，因此也与SM汤川耦合本身的起源有很深的关系。我们表明，现实的SU（3）味对称性与自发CP破坏正确再现SM汤川矩阵可以同时解决这两个问题，而无需特别修改的超对称模型。我们分析了这些模型中的轻子电偶极矩和轻子味破坏过程。我们表明，电子EDM和衰变μ-> e γ自然是在拟议的实验范围内，如果sfermion质量是可测量的大型强子对撞机。
Within the Standard Model Effective Field Theory framework, with operators up to dimension 6, we perform a model-independent analysis of the lepton-flavour-violating processes involving tau leptons. Namely, we study hadronic tau decays and $\ell$--$τ$ conversion in nuclei, with $\ell = e,μ$. Based on available experimental limits, we establish constraints on the Wilson coefficients of the operators contributing to these processes. Our work paves the way to extract the related information from Belle II and foreseen future experiments.
Heavy flavour physics provides excellent opportunities to indirectly search for new physics at very high energy scales and to study hadron properties for deep understanding of the strong interaction. The LHCb experiment has been playing a leading role in the study of heavy flavour physics since the start of the LHC operations about ten years ago, and made a range of high-precision measurements and unexpected discoveries, which may have far-reaching implications on the field of particle physics. This review highlights a selection of the most influential physics results on CP violation, rare dec…
The singly charged $SU(2)_L$ singlet scalar, with its necessarily flavour violating couplings to leptons, lends itself particularly well for an explanation of the Cabibbo Angle Anomaly and of hints for lepton flavour universality violation in $τ\to μ\bar νν$. In a setup addressing both anomalies, we predict loop-induced effects in $τ\to eγ$ and in $τ\to eμμ$. A recast of ATLAS selectron and smuon searches allows us to derive a coupling-independent lower limit of $\approx 200$ GeV on the mass of the singly charged singlet scalar. At a future $e^+e^-$ collider, dark matter mono-photon searches c…
Two-Higgs-doublet models with Minimal Flavour Violation
在两个希格斯偶极子模型中的树级味道变化中性电流可以通过保护味道或味道盲对称性的破坏来抑制，但只有第一个选择，通过应用最小味道违反假设来实现，在量子校正下是稳定的。此外，一个富含味盲相的具有最小味破坏的双Higgs二重态模型可以解释最近在Delta F = 2跃迁中发现的异常现象，即B_s混合中的CP破坏相以及S_s_K和S_s_K之间的张力。
我们回顾了标准模型中的味物理和CP破坏的主要方面。在介绍了包括弱衰变主公式在内的该领域的宏观观点之后，我们讨论了i）幺正三角形的标准分析，ii）比率ε '/ε'，iii）稀有衰变K^+ -> pi^+ nu barnu和K_L -> pi ^0 nu barnu，iv）B衰变中的CP破坏和v）具有最小味破坏的模型。我们的评论以20个问题结束，希望在未来几年内得到回答。
