|
|
LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). First observations of (B)over-bar(s)(0) -> D+D-, Ds+D- and D-0(D)over-bar(0) decays. Phys. Rev. D, 87(9), 092007–12pp.
Abstract: First observations and measurements of the branching fractions of the (B) over bar (0)(s) -> D+D-, (B) over bar (0)(s) -> Ds+D- and (B) over bar (0)(s) -> D-0(D) over bar (0) decays are presented using 1.0 fb(-1) of data collected by the LHCb experiment. These branching fractions are normalized to those of (B) over bar (0) -> D+D-, B-0 -> D-Ds+ and B- -> (DDs-)-D-0, respectively. An excess of events consistent with the decay (B) over bar (0) -> D-0(D) over bar (0) is also seen, and its branching fraction is measured relative to that of B- -> D0Ds-. Improved measurements of the branching fractions B((B) over bar (0)(s) -> Ds+Ds-) and B(B- -> (DDs-)-D-0) are reported, each relative to B(B-0 -> D-Ds+). The ratios of branching fractions are B((B) over bar (0)(s) -> D+D-)/B((B) over bar (0) -> D+D-) = 1.08 +/- 0.20 +/- 0.10, B((B) over bar (0)(s) -> Ds+D-)/B(B-0 -> D-Ds+) = 0.050 +/- 0.008 +/- 0.004, B((B) over bar (0)(s) -> D-0(D) over bar (0))/B((B) over bar (-) -> (DDs-)-D-0) = 0.019 +/- 0.003 +/- 0.003, B((B) over bar (0) -> D-0(D) over bar (0))/B(B- -> (DDs-)-D-0) < 0.0024 at 90% CL, B(<(B)over bar>(0)(s) -> D-s(+)(D) over bar (-)(s))/B(B-0 -> D-Ds+) = 0.56 +/- 0.03 +/- 0.04, B(B -> (DDs)-D-0)/B(B-0 -> D-Ds+) = 1.22 +/- 0.02 +/- 0.07, where the uncertainties are statistical and systematic, respectively.
|
|
|
|
LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). First observations of the rare decays B (+) -> K (+)pi (+)pi (-)mu(+)mu (-) and B (+)-> phi K (+)mu(+)mu (-). J. High Energy Phys., 10(10), 064–18pp.
Abstract: First observations of the rare decays B (+) -> K (+)pi (+) pi (-) μ(+) μ(-) and B (+)-> phi K+ mu(+)mu(-) are presented using data corresponding to an integrated luminosity of 3.0 fb(-1), collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The branching fractions of the decays are B(B (+) -> K (+)pi (+) pi (-) μ(+) μ(-) ) = (4.36 (-0.27) (+0.29) (stat) +/- 0.21 (syst) +/- (norm)) x 10(-7), B(B (+)-> phi K+ mu(+)mu(-)) = (0.82 (+0.19)(-0.17) (stat) (+0.10)(-0.04) (syst) +/- 0.27 (norm)) x 10(-7) where the uncertainties are statistical, systematic, and due to the uncertainty on the branching fractions of the normalisation modes. A measurement of the differential branching fraction in bins of the invariant mass squared of the dimuon system is also presented for the decay B (+) -> K (+)pi (+) pi (-) μ(+) μ(-)
|
|
|
|
LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., et al. (2016). First study of the CP-violating phase and decay-width difference in B-s(0) -> psi(2S)phi decays. Phys. Lett. B, 762, 253–262.
Abstract: A time-dependent angular analysis of B-s(0) -> psi(2S)phi decays is performed using data recorded by the LHCb experiment. The data set corresponds to an integrated luminosity of 3.0fb(-1) collected during Run 1 of the LHC. The CP-violating phase and decay-width difference of the B-s(0) system are measured to be phi(s)=0.23(-0.28)(+0.29)+/- 0.02rad and Delta Gamma(s)=0.066(-0.044)(+0.041)+/- 0.007ps(-1), respectively, where the first uncertainty is statistical and the second systematic. This is the first time that phi s and Delta Gamma s have been measured in a decay containing the psi(2S) resonance.
|
|
|
|
LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Forward production of Upsilon mesons in pp collisions at root s=7 and 8 TeV. J. High Energy Phys., 11(11), 103–34pp.
Abstract: The production of Upsilon mesons in pp collisions at root s = 7 and 8 TeV is studied with the LHCb detector using data samples corresponding to an integrated luminosity of 1 fb(-1) and 2 fb(-1) respectively. The production cross-sections and ratios of cross-sections are measured as functions of the meson transverse momentum p and rapidity y, for p < 30 GeV/c and 2.0 < y < 4.5.
|
|
|
|
LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2024). Helium identification with LHCb. J. Instrum., 19(2), P02010–23pp.
Abstract: The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using pp collision data at root s = 13 TeV recorded by the LHCb experiment in the years 2016 to 2018, corresponding to an integrated luminosity of 5.5 fb(-1). A total of around 10(5) helium and antihelium candidates are identified with negligible background contamination. The helium identification efficiency is estimated to be approximately 50% with a corresponding background rejection rate of up to O(10(12)). These results demonstrate the feasibility of a rich programme of measurements of QCD and astrophysics interest involving light nuclei.
|
|
