8 research outputs found
Chiral Extrapolation of the Strangeness Changing K pi Form Factor
We perform a chiral extrapolation of lattice data on the scalar K pi form
factor and the ratio of the kaon and pion decay constants within Chiral
Perturbation Theory to two loops. We determine the value of the scalar form
factor at zero momentum transfer, at the Callan-Treiman point and at its soft
kaon analog as well as its slope. Results are in good agreement with their
determination from experiment using the standard couplings of quarks to the W
boson. The slope is however rather large. A study of the convergence of the
chiral expansion is also performed.Comment: few minor change
Precise measurements of the properties of the B-1(5721)(0,+) and B-2*(5747)(0,+) states and observation of B-+,B-0 pi(-,+) mass structures
Invariant mass distributions of B+pi- and B0pi+ combinations are investigated
in order to study excited B mesons. The analysis is based on a data sample
corresponding to 3.0 fb-1 of pp collision data, recorded by the LHCb detector
at centre-of-mass energies of 7 and 8 TeV. Precise measurements of the masses
and widths of the B_1(5721)^(0,+) and B_2*(5747)^(0,+) states are reported.
Clear enhancements, particularly prominent at high pion transverse momentum,
are seen over background in the mass range 5850--6000 MeV in both B+pi- and
B0pi+ combinations. The structures are consistent with the presence of four
excited B mesons, labelled B_J(5840)^(0,+) and B_J(5960)^(0,+), whose masses
and widths are obtained under different hypotheses for their quantum numbers.Comment: 29 pages, 5 Figures, 8 Table