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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., 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., 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. (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), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., Remon Alepuz, C., et al. (2023). Amplitude analysis of the Lambdac+ -> p K- pi+ decay and Lambdac+ baryon polarization measurement in semileptonic beauty hadron decays. Phys. Rev. D, 108(1), 012023–27pp.
Abstract: An amplitude analysis of A+c – pK- & pi;+ decays together with a measurement of the A+c polarization vector in semiOleptonic beauty hadron decays is presented. A sample of 400 000 candidates is selected from proton-proton collisions recorded by the LHCb detector at a center-of-mass energy of 13 TeV. An amplitude model is developed and the resonance fractions as well as two- and three-body decay parameters are reported. The mass and width of the Ao2000 thorn state are also determined. A significant A+c polarization is found. A large sensitivity of the A+c – pK-& pi;+ decay to the polarization is seen, making the amplitude model suitable for A+c polarization measurements in other systems.
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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. (2017). Search for Baryon-Number Violating Xi(0)(b) Oscillations. Phys. Rev. Lett., 119(18), 181807–9pp.
Abstract: A search for baryon-number violating Xi(0)(b) oscillations is performed with a sample of pp collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 3 fb(-1). The baryon number at the moment of production is identified by requiring that the Xi(0)(b) come from the decay of a resonance Xi(b)*(-) -> Xi(0)(b)pi(-) or Xi(b)'(-) -> Xi(0)(b)pi(-) and the baryon number at the moment of decay is identified from the final state using the decays Xi(0)(b) -> Xi(0)(c)pi(-) , Xi(+-)(c) -> pK(-)pi(+). No evidence of baryon-number violation is found, and an upper limit at the 95% confidence level is set on the oscillation rate of omega < 0.08 ps(-1), where. is the associated angular frequency.
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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). First observation of forward Z -> b(b)over-bar production in pp collisions at root s=8 TeV. Phys. Lett. B, 776, 430–439.
Abstract: The decay Z -> b (b) over bar is reconstructed in pp collision data, corresponding to 2 fb(-1) of integrated luminosity, collected by the LHCb experiment at a centre-of-mass energy of root s = 8 TeV. The product of the Z production cross-section and the Z -> b (b) over bar branching fraction is measured for candidates in the fiducial region defined by two particle-level b-quark jets with pseudorapidities in the range 2.2 < eta < 4.2, with transverse momenta p(T) > 20 GeV and dijet invariant mass in the range 45 < m(jj) < 165 GeV. From a signal yield of 5462 +/- 763 Z -> b (b) over bar events, where the uncertainty is statistical, a production cross-section times branching fraction of 332 +/- 46 +/- 59 pb is obtained, where the first uncertainty is statistical and the second systematic. The measured significance of the signal yield is 6.0 standard deviations. This measurement represents the first observation of the Z -> b (b) over bar production in the forward region of pp collisions.
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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). Study of the psi(2)(3823) and chi(c1)(3872) states in B+->(J/psi pi(+)pi(-))K(+)decays. J. High Energy Phys., 08(8), 123–29pp.
Abstract: The decays B+-> J/psi pi(+)pi(-)K(+)are studied using a data set corresponding to an integrated luminosity of 9 fb(-1)collected with the LHCb detector in proton-proton collisions between 2011 and 2018. Precise measurements of the ratios of branching fractions with the intermediate psi(2)(3823), chi(c1)(3872) and psi(2S) states are reported. The values areBB+->psi 2(“>3823K+xB psi 2(”>3823 -> J/psi pi+pi-BB+->chi c1>3872K+xB chi c1>3872 -> J/psi pi+pi-=>3.56 +/- 0.67 +/- 0.11x10-2,BB+->psi 2>3823K+xB psi 2>3823 -> J/psi pi+pi-BB+->psi>2SK+xB psi>2S -> J/psi pi+pi-=>1.31 +/- 0.25 +/- 0.04x10-3,BB+->chi c1>3872K+xB chi c1>3872 -> J/psi pi+pi-BB+->psi>2SK+xB psi>2S -> J/psi pi+pi-= where the first uncertainty is statistical and the second is systematic. The decay of B+->psi(2)(3823)K(+)with psi(2)(3823)-> J/psi pi(+)pi(-)is observed for the first time with a significance of 5.1 standard deviations. The mass differences between the psi(2)(3823), chi(c1)(3872) and psi(2S) states are measured to be m chi c1>3872-m psi 2>3823=47. 50 +/- 0.53 +/- 0.13MeV/c2,m psi 2 2S=185.49 +/- 0.06 +/- 0.03MeV/c2, resulting in the most precise determination of the chi(c1)(3872) mass. The width of the psi(2)(3823) state is found to be below 5.2 MeV at 90% confidence level. The Breit-Wigner width of the chi(c1)(3872) state is measured to be Gamma chi c13872BW=0.96-0.18+0.19 +/- 0.21MeV={0.96}_{-0.18}<^>{+0.19}\pm 0.21\;\mathrm{MeV} which is inconsistent with zero by 5.5 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. (2020). Study of the lineshape of the chi(c1) (3872) state. Phys. Rev. D, 102(9), 092005–20pp.
Abstract: A study of the lineshape of the chi(c1) (3872) state is made using a data sample corresponding to an integrated luminosity of 3 fb(-1) collected in pp collisions at center-of-mass energies of 7 and 8 TeV with the LHCb detector. Candidate chi(c1)(3872) and psi(2S) mesons from b-hadron decays are selected in the J/psi pi(+)pi(-) decay mode. Describing the lineshape with a Breit-Wigner function, the mass splitting between the chi(c1 )(3872) and psi(2S) states, Delta m, and the width of the chi(c1 )(3872) state, Gamma(Bw), are determined to be (Delta m=185.598 +/- 0.067 +/- 0.068 Mev,)(Gamma BW=1.39 +/- 0.24 +/- 0.10 Mev,) where the first uncertainty is statistical and the second systematic. Using a Flatte-inspired model, the mode and full width at half maximum of the lineshape are determined to be (mode=3871.69+0.00+0.05 MeV.)(FWHM=0.22-0.04+0.13+0.07+0.11-0.06-0.13 MeV, ) An investigation of the analytic structure of the Flatte amplitude reveals a pole structure, which is compatible with a quasibound D-0(D) over bar*(0) state but a quasivirtual state is still allowed at the level of 2 standard deviations.
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