579 research outputs found
Observation of Two New Excited Ξb0 States Decaying to Λb0 K-π+
Two narrow resonant states are observed in the Λb0K-π+ mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6 fb-1. The minimal quark content of the Λb0K-π+ system indicates that these are excited Ξb0 baryons. The masses of the Ξb(6327)0 and Ξb(6333)0 states are m[Ξb(6327)0]=6327.28-0.21+0.23±0.12±0.24 and m[Ξb(6333)0]=6332.69-0.18+0.17±0.03±0.22 MeV, respectively, with a mass splitting of Δm=5.41-0.27+0.26±0.12 MeV, where the uncertainties are statistical, systematic, and due to the Λb0 mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ[Ξb(6327)0]<2.20(2.56) and Γ[Ξb(6333)0]<1.60(1.92) MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths, and resonant structure of the new states are in good agreement with the expectations for a doublet of 1D Ξb0 resonances
Enhancement strategies for transdermal drug delivery systems: current trends and applications
Search for beautiful tetraquarks in the <i>ϒ</i>(1<i>S</i>)μ<sup>+</sup>μ<sup>−</sup> invariant-mass spectrum
International audienceThe ϒ(1S)μμ invariant-mass distribution is investigated for a possible exotic meson state composed of two b quarks and two quarks, . The analysis is based on a data sample of pp collisions recorded with the LHCb detector at centre-of-mass energies , 8 and 13 TeV, corresponding to an integrated luminosity of 6.3 fb. No significant excess is found, and upper limits are set on the product of the production cross-section and the branching fraction as functions of the mass of the state. The limits are set in the fiducial volume where all muons have pseudorapidity in the range [2.0, 5.0], and the state has rapidity in the range [2.0, 4.5] and transverse momentum less than 15 GeV/c
Measurement of the photon polarization in decays
The photon polarization in transitions is measured for the
first time in radiative b-baryon decays exploiting the unique spin structure of
decays. A data sample corresponding to an
integrated luminosity of collected by the LHCb experiment in
collisions at a center-of-mass energy of is used. The photon
polarization is measured to be , where the first uncertainty is
statistical and the second systematic. This result is in agreement with the
Standard Model prediction and previous measurements in b-meson decays.
Charge-parity breaking effects are studied for the first time in this
observable and found to be consistent with symmetry.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-030.html (LHCb
public pages
Study of the decay with an amplitude analysis of decays
International audienceAn amplitude analysis of B → (ππ)(Kπ) decays is performed in the two-body invariant mass regions 300 < m(ππ) < 1100 MeV/c, accounting for the ρ, ω, f(500), f(980) and f(1370) resonances, and 750 < m(Kπ) < 1200 MeV/c, which is dominated by the K(892) meson. The analysis uses 3 fb of proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The CP averages and asymmetries are measured for the magnitudes and phase differences of the con- tributing amplitudes. The CP-averaged longitudinal polarisation fractions of the vector-vector modes are found to be = 0.164 ± 0.015 ± 0.022 and = 0.68 ± 0.17 ± 0.16, and their CP asymmetries, = −0.62 ± 0.09 ± 0.09 and = −0.13 ± 0.27 ± 0.13, where the first uncertainty is statistical and the second systematic
Angular analysis of and decays and search for violation
The first full angular analysis and an updated measurement of the decay-rate
asymmetry of the and decays are reported. The analysis uses proton-proton
collision data collected with the LHCb detector at centre-of-mass energies of
7, 8 and 13 TeV. The data set corresponds to an integrated luminosity of 9
fb. The full set of -averaged angular observables and their
asymmetries are measured as a function of the dimuon invariant mass. The
results are consistent with expectations from the standard model and with
symmetry.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-035.html (LHCb
public pages
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