Abstract
We present a lattice determination of the vector and scalar form factors of the D → π(K)lv semileptonic decays, which are relevant for the extraction of the CKM matrix elements |Vcd| and |Vcs| from experimental data. Our analysis is based on the gauge configurations produced by the European Twisted Mass Collaboration with Nf = 2 + 1 +1 flavors of dynamical quarks. We simulated at three different values of the lattice spacing and with pion masses as small as 210 MeV. The matrix elements of both vector and scalar currents are determined for a plenty of kinematical conditions in which parent and child mesons are either moving or at rest. Lorentz symmetry breaking due to hypercubic effects is clearly observed in the data and included in the decomposition of the current matrix elements in terms of additional form factors. After the extrapolations to the physical pion mass and to the continuum limit the vector and scalar form factors are determined in the whole kinematical region from q2 = 0 up to [see formula in PDF] accessible in the experiments, obtaining a good overall agreement with experiments, except in the region at high values of q2 where some deviations are visible.
Highlights
Introduction and simulation detailsFlavor physics, the branch of particle physics that studies transitions between different quarks and leptons, plays a fundamental role both for an indirect search of New Physics (NP) and to put stringent constraint on the Standard Model (SM)
In this contribution we present the first N f = 2 + 1 + 1 LQCD calculation of the vector and scalar form factors f+Dπ(K)(q2) and f0Dπ(K)(q2), governing the semileptonic D → π(K) ν decays, relevant for the extraction of the CKM matrix elements |Vcd| and |Vcs| [1]
The analysis has been carried out using the gauge configurations generated by the European Twisted Mass Collaboration (ETMC) with N f = 2 + 1 + 1 dynamical quarks, which include in the sea, besides two light mass-degenerate quarks, the strange and the charm quarks [2, 3]
Summary
The branch of particle physics that studies transitions between different quarks and leptons, plays a fundamental role both for an indirect search of New Physics (NP) and to put stringent constraint on the Standard Model (SM). Because of its highly non trivial structure, it is sensitive to many NP scenarios In this contribution we present the first N f = 2 + 1 + 1 LQCD calculation of the vector and scalar form factors f+Dπ(K)(q2) and f0Dπ(K)(q2), governing the semileptonic D → π(K) ν decays, relevant for the extraction of the CKM matrix elements |Vcd| and |Vcs| [1]. We present the subtraction of such hypercubic effects and the determination of the physical, Lorentz-invariant, semileptonic vector and scalar form factors in the whole experimentally accessible range in q2, i.e. from q2 = 0 up to q2max = (MD − Mπ(K)), at variance with respect to existing LQCD calculations
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