LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., et al. (2017). Measurement of the B-+/- production asymmetry and the CP asymmetry in B-+/-> J/psi K-+/- decays. Phys. Rev. D, 95(5), 052005–13pp.
Abstract: The B-+/- meson production asymmetry in pp collisions is measured using B-+/- -> (D) over bar (0)pi(+) decays. The data were recorded by the LHCb experiment during Run 1 of the LHC at center- of- mass energies of ffiffiffi root s = 7 and 8 TeV. The production asymmetries, integrated over transverse momenta in the range 2 < p(T) < 30 GeV/c, and rapidities in the range 2.1 < y < 4.5 are measured to be A(prod)(B+, root s = 7 TeV) = (-0.41 +/- 0.49 +/- 0.10) x 10(- 2), A(prod)(B+, root s = 8 TeV = (- 0.53 +/- 0.31 +/- 0.10) x 10(-2), where the first uncertainties are statistical and the second are systematic. These production asymmetries are used to correct the raw asymmetries of (B+ -> J/psi K+) decays, thus allowing a measurement of the CP asymmetry, A(CP)(B+-> J/psi K+) = (0.09 +/- 0.27 +/- 0.07) x 10(-2)
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., et al. (2017). Search for long-lived scalar particles in B+-> K+chi(mu(+) mu(-)) decays. Phys. Rev. D, 95(7), 071101–9pp.
Abstract: A search for a long-lived scalar particle. is performed, looking for the decay B+ -> K+chi with chi ->mu(+)mu(-) pp collision data corresponding to an integrated luminosity of 3 fb(-1), collected by the LHCb experiment at center-of-mass energies of root s = 7 and 8 TeV. This new scalar particle, predicted by hidden sector models, is assumed to have a narrow width. The signal would manifest itself as an excess in the dimuon invariant mass distribution over the Standard Model background. No significant excess is observed in the accessible ranges of mass 250 < m(chi) < 4700 MeV/c(2) and lifetime 0.1 < tau(chi) < 1000 ps. Upper limits on the branching fraction B(B-broken vertical bar -> K-broken vertical bar chi(mu(vertical bar) mu(-))) at 95% confidence level are set as a function of m(chi) and tau(chi), varying between 2 x 10(-10) and 10(-7). These are the most stringent limits to date. The limits are interpreted in the context of a model with a light inflaton particle.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2018). Search for weakly decaying b-flavored pentaquarks. Phys. Rev. D, 97(3), 032010–11pp.
Abstract: Investigations of the existence of pentaquark states containing a single b (anti) quark decaying weakly into four specific final states J/psi K+pi(-)p, J/psi K-pi(-)p, J/psi K-pi(+)p, and J/psi phi(1020)p are reported. The data sample corresponds to an integrated luminosity of 3.0 fb(-1) in 7 and 8 TeV pp collisions acquired with the LHCb detector. Signals are not observed and upper limits are set on the product of the production cross section times branching fraction with respect to that of the A(b)(0).
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Measurement of psi (2S) production cross-sections in proton-proton collisions at v s=7 and 13 TeV. Eur. Phys. J. C, 80(3), 185–23pp.
Abstract: The cross-sections of.(2S) meson production in proton-proton collisions at v s = 13 TeV are measured with a data sample collected by the LHCb detector corresponding to an integrated luminosity of 275 pb-1. The production cross-sections for prompt.(2S) mesons and those for.(2S) mesons from b-hadron decays (.(2S)-from-b) are determined as functions of the transverse momentum, pT, and the rapidity, y, of the.(2S) meson in the kinematic range 2 < pT < 20 GeV/c and 2.0 < y < 4.5. The production cross-sections integrated over this kinematic region are s(prompt.(2S), 13 TeV) = 1.430 +/- 0.005 (stat) +/- 0.099 (syst) μb, s(.(2S)-from-b, 13 TeV) = 0.426 +/- 0.002 (stat) +/- 0.030 (syst) μb. A new measurement of.(2S) production cross-sections in pp collisions at v s = 7 TeV is also performed using data collected in 2011, corresponding to an integrated luminosity of 614 pb-1. The integrated production cross-sections in the kinematic range 3.5 < pT < 14 GeV/c and 2.0 < y < 4.5 are s(prompt.(2S), 7 TeV) = 0.471 +/- 0.001 (stat) +/- 0.025 (syst) μb, s(.(2S)-from-b, 7 TeV) = 0.126 +/- 0.001 (stat) +/- 0.008 (syst) μb. All results show reasonable agreement with theoretical calculations.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2019). Measurement of the branching fractions of the decays D+ -> K-K+K+, D+ -> pi-pi(+) K+ and D-s(+) -> pi-K+K+. J. High Energy Phys., 03(3), 176–24pp.
Abstract: The branching fractions of the doubly Cabibbo-suppressed decays D+ ! K, D+ ! and D+ s ! are measured using the decays D+ ! K and D+ s ! K as normalisation channels. The measurements are performed using proton-proton collision data collected with the LHCb detector at a centre-of-mass energy of 8TeV, corresponding to an integrated luminosity of 2.0 fb. The results are B (D+ ! K) B (D+ ! K) = (6 : 541 0 : 025 0 : 042) 10 B (D+ ! ) B (D+ ! K) = (5 : 231 0 : 009 0 : 023) 10 B (D+ s ! ) B (D+ s ! K) = (2 : 372 0 : 024 0 : 025) 10 where the uncertainties are statistical and systematic, respectively. These are the most precise measurements up to date.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2019). Measurement of the ratio of branching fractions of the decays0(2S) and arrange Lambda. J. High Energy Phys., 03(3), 126–16pp.
Abstract: Using pp collisions corresponding to 3 fb integrated luminosity, recorded by the LHCb experiment at centre- of- mass energies of 7 and 8 TeV, the ratio of branching fractions B (0b ! (2 S) ) =B (0b ! J= ) = 0 : 513 0 : 023 (stat) 0 : 016 (syst) 0 : 011 (B) is determined. The first uncertainty is statistical, the second is systematic and the third is due to the external branching fractions used.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2019). Measurement of the relative B- -> D-0 / D*(0) / D**(0)mu(-)(nu)over-bar(mu) branching fractions using B- mesons from (B)over-bar(S)(2)*(0) decays. Phys. Rev. D, 99(9), 092009–16pp.
Abstract: The decay of the narrow resonance (B) over bar (s2)*(0 )-> B(-)K(+)can be used to determine the B- momentum in partially reconstructed decays without any assumptions on the decay products of the r meson. This technique is employed for the first time to distinguish contributions from D-0, D*(0), and higher-mass charmed states (D(0)) in semileptonic B- decays by using the missing-mass distribution. The measurement is performed using a data sample corresponding to an integrated luminosity of 3.0 fb(-1) collected with the LHCb detector in pp collisions at center-of-mass energies of 7 and 8 TeV. The resulting branching fractions relative to the inclusive B- -> (DX)-X-0 mu(-)(nu) over bar (mu )are f(D)(0)= B(B- -> D-0 mu(-)(nu) over bar mu/B(B- ->(DX)-D- -X-0 mu(-)(nu) over bar (mu))( )= 0.25( )+/- 0.06, f( D)(0 )= B(B- -> (D(0) -> (DX)-X-0)mu(-)(nu) over bar (mu))/B(B--> (DX)-X-0 mu(-)(nu) over bar (mu)) = 0.21 +/- 0.07, with f(D)*(0) = 1 – f(D)(0) – f(D)(0) making up the remainder.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Precision measurement of the Xi(++)(cc) mass. J. High Energy Phys., 02(2), 049–18pp.
Abstract: A measurement of the Xi cc++ candidates are reconstructed via the decay modes Xi cc++->?c+K-pi+pi+ and Xi cc++->Xi c+pi+. The result, 3621.55 +/- 0.23 (stat) +/- 0.30 (syst) MeV/c(2), is the most precise measurement of the Xi cc++ mass to date.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2019). Search for Lepton-Universality Violation in B+ -> K(+)l(+)l(-) Decays. Phys. Rev. Lett., 122(19), 191801–13pp.
Abstract: A measurement of the ratio of branching fractions of the decays B+ -> K+mu(+)mu(-) and B+ -> K(+)e(+)e(-) is presented. The proton-proton collision data used correspond to an integrated luminosity of 5.0 fb(-1) recorded with the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. For the dilepton mass-squared range 1.1 < q(2) < 6.0 GeV2/c(4) the ratio of branching fractions is measured to be R-K = 0.846(-0.054-0.014)(+0.060+0.016), where the first uncertainty is statistical and the second systematic. This is the most precise measurement of R-K to date and is compatible with the standard model at the level of 2.5 standard deviations.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2019). Observation of B-(s)(0) -> J/psi p(p)over-bar Decays and Precision Measurements of the B-(s)(0) Masses. Phys. Rev. Lett., 122(19), 191804–10pp.
Abstract: The first observation of the decays B-(s)(0) -> J/psi p (p) over bar is reported, using proton-proton collision data corresponding to an integrated luminosity of 5.2 fb(-1), collected with the LHCb detector. These decays are suppressed due to limited available phase space, as well as due to Okubo-Zweig-Iizuka or Cabibbo suppression. The measured branching fractions are beta(B-(s)(0) -> J/psi p (p) over bar). [4.51 +/- 0.40(stat)+/- 0.44(syst)] x 10(-7), BB(s)0 -> J/psi p (p) over bar) = 3.58 +/- 0.19(stat) 0.39(syst)] x 10(-6). For the B-s(0) meson, the result is much higher than the expected value of O(10(-9)). The small available phase space in these decays also allows for the most precise single measurement of both the B-0 mass as 5279.74 +/- 0.30(stat) 0.10(syst) MeV and the B-s(0) mass as 5366.85 +/- 0.19(stat) +/- 0.13(syst) MeV.
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