BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2014). Cross sections for the reactions e+e- -> K0S K0L, K0S K0L pi+ pi-, K0S K0S pi+ pi-, and K0S K0S K+ K- from events with initial- state radiation. Phys. Rev. D, 89(9), 092002–25pp.
Abstract: We study the processes e+e- -> K0S K0L gamma, K0S K0L pi+ pi- gamma, K0S K0S pi+ pi- gamma, and K0S K0S K+ K- gamma, where the photon is radiated from the initial state, providing cross section measurements for the hadronic states over a continuum of center-of-mass energies. The results are based on 469 fb-1 of data collected with the BABAR detector at SLAC. We observe the phi(1020) resonance in the K0S K0L final state and measure the product of its electronic width and branching fraction with about 3% uncertainty. We present a measurement of the e+e- -> K0S K0L cross section in the energy range from 1.06 to 2.2 GeV and observe the production of a resonance at 1.67 GeV. We present the first measurements of the e+e- -> K0S K0L pi+ pi-, K0S K0S pi+ pi-, and K0S K0S K+ K- cross sections and study the intermediate resonance structures. We obtain the first observations of J/Psi decay to the K0S K0L pi+ pi-, K0S K0S pi+ pi-, and K0S K0S K+ K- final states.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). First observation and amplitude analysis of the B- -> D+K-pi(-) decay. Phys. Rev. D, 91(9), 092002–24pp.
Abstract: The B- -> D+K-pi(-) decay is observed in a data sample corresponding to 3.0 fb(-1) of pp collision data recorded by the LHCb experiment during 2011 and 2012. Its branching fraction is measured to be B(B- -> D+K-pi(-)) = (7.31 +/- 0.19 +/- 0.22 +/- 0.39) x 10(-5) where the uncertainties are statistical, systematic and from the branching fraction of the normalization channel B- -> D+pi(-)pi(-), respectively. An amplitude analysis of the resonant structure of the B- -> D+K-pi(-) decay is used to measure the contributions from quasi-two-body B- -> D-0* (2400)K-0(-), B- -> D-2* (2460)K-0(-), and B- -> D-J* (2760)K-0(-) decays, as well as from nonresonant sources. The D-J* (2760)(0) resonance is determined to have spin 1.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2014). Measurements of direct CP asymmetries in B -> X-s gamma decays using sum of exclusive decays. Phys. Rev. D, 90(9), 092001–12pp.
Abstract: We measure the direct CP violation asymmetry, A(CP), in B -> X-s gamma and the isospin difference of the asymmetry, Delta A(CP), using 429 fb(-1) of data collected at Upsilon(4S) resonance with the BABAR detector at the PEP- II asymmetric- energy e(+)e(-) storage rings operating at the SLAC National Accelerator Laboratory. B mesons are reconstructed from ten charged B final states and six neutral B final states. We find A(CP) = +(1.7 +/- 1.9 +/- 1.0)%, which is in agreement with the Standard Model prediction and provides an improvement on the world average. Moreover, we report the first measurement of the difference between A(CP) for charged and neutral decay modes, Delta A(CP) = +(5.0 +/- 3.9 +/- 1.5)%. Using the value of Delta A(CP), we also provide 68% and 90% confidence intervals on the imaginary part of the ratio of theWilson coefficients corresponding to the chromomagnetic dipole and the electromagnetic dipole transitions.
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LHCb Collaboration(Aaij, R. et al), Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2021). Observation of Multiplicity Dependent Prompt chi(c1) (3872) and psi (2S) Production in pp Collisions. Phys. Rev. Lett., 126(9), 092001–11pp.
Abstract: The production of chi(c1)(3872) and psi(2S) hadrons is studied as a function of charged particle multiplicity in pp collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2 fb(-1). For both states, the fraction that is produced promptly at the collision vertex is found to decrease as charged particle multiplicity increases. The ratio of chi(c1) (3872) to psi(2S) cross sections for promptly produced particles is also found to decrease with multiplicity, while no significant dependence on multiplicity is observed for the equivalent ratio of particles produced away from the collision vertex in b-hadron decays. This behavior is consistent with a calculation that models the chi(c1) (3872) structure as a compact tetraquark. Comparisons with model calculations and implications for the binding energy of the chi(c1)(3872) state are discussed.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2021). Study of the reactions e(+)e(-) -> 2(pi(+)pi(-))pi(0)pi(0)pi(0) and 2(pi(+)pi(-))pi(0)pi(0)eta at center-of-mass energies from threshold to 4.5 GeV using initial-state radiation. Phys. Rev. D, 103(9), 092001–21pp.
Abstract: We study the processes e(+)e(-) -> 2(pi(+)pi(-))pi(0)pi(0)pi(0)gamma and 2(pi(+)pi(-))pi(0)pi(0)eta gamma in which an energetic photon is radiated from the initial state. The data were collected with the BABAR detector at SLAC. About 14 000 and 4700 events, respectively, are selected from a data sample corresponding to an integrated luminosity of 469 fb(-1). The invariant mass of the hadronic final state defines the effective e(+)e(-) center-of-mass energy. The center-of-mass energies range from threshold to 4.5 GeV. From the mass spectra, the first ever measurements of the e(+)e(-) -> 2(pi(+)pi(-))pi(0)pi(0)pi(0) and the e(+)e(-) -> 2(pi(+)pi(-))pi(0)pi(0)eta cross sections are performed. The contributions from omega pi(+)pi(-)pi(0)pi(0), eta 2(pi(+)pi(-)), and other intermediate states are presented. We observe the J/psi and psi(2S) in most of these final states and measure the corresponding branching fractions, many of them for the first time.
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