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BABAR Collaboration(del Amo Sanchez, P. et al), Martinez-Vidal, F., & Oyanguren, A. (2016). Time-dependent analysis of B-0 -> K-S(0)pi(-)pi(+) gamma decays and studies of the K+pi(-)pi(+) system in B+ -> K+pi(-)pi(+)gamma decays. Phys. Rev. D, 93(5), 052013–29pp.
Abstract: We measure the time-dependent CP asymmetry in the radiative-penguin decay B-0 -> K-S(0)pi(-)pi(+)gamma, using a sample of 471 x 10(6) Upsilon(4S) -> B (B) over bar events recorded with the BABAR detector at the PEP-II e(+)(e) over tilde (-) storage ring at SLAC. Using events with m(K pi pi) < 1.8 GeV/c(2), we measure the branching fractions of B+ -> K+pi(-)pi(+)gamma and B-0 -> K-S(0)pi(-)pi(+)gamma, the branching fractions of the kaonic resonances decaying to K+pi(-)pi(+)gamma, as well as the overall branching fractions of the B+ -> rho K-0(+.)gamma, B+ -> K*(0)pi(+)gamma. and S-wave B+ -> (K pi)(0)(*0) pi(+)gamma components. For events from the rho mass band, we measure the CP-violating parameters SKS0 pi+pi-gamma = 0.14 +/- 0.25 +/- 0.03 and CKS0 pi+pi-gamma = -0.39 +/- 0.20(-0.02)(+0.003), where the first uncertainties are statistical and the second are systematic. We extract from this measurement the time-dependent CP asymmetry related to the CP eigenstate rho K-0(S)0 and obtain S-KS(0) = -0.18 +/- 0.32(-0.05)(+0.06), which provides information on the photon polarization in the underlying b -> s gamma transition.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., Fiorini, L., et al. (2016). Centrality, rapidity, and transverse momentum dependence of isolated prompt photon production in lead-lead collisions at root S-NN=2.76 TeV measured with the ATLAS detector. Phys. Rev. C, 93(3), 034914–28pp.
Abstract: Prompt photon production in root S-NN = 2.76-TeV Pb + Pb collisions has been measured by the ATLAS experiment at the Large Hadron Collider using data collected in 2011 with an integrated luminosity of 0.14 nb(-1). Inclusive photon yields, scaled by the mean nuclear thickness function, are presented as a function of collision centrality and transverse momentum in two pseudorapidity intervals, vertical bar eta vertical bar < 1.37 and 1.52 <= vertical bar eta vertical bar < 2.37. The scaled yields in the two pseudorapidity intervals, as well as the ratios of the forward yields to those at midrapidity, are compared to the expectations from next-to-leading-order perturbative QCD (pQCD) calculations. The measured cross sections agree well with the predictions for proton-proton collisions within statistical and systematic uncertainties. Both the yields and the ratios are also compared to two other pQCD calculations, one which uses the isospin content appropriate to colliding lead nuclei and another which includes nuclear modifications to the nucleon parton distribution functions.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2016). Measurement of angular asymmetries in the decays B -> K*l(+) l(+). Phys. Rev. D, 93(5), 052015–16pp.
Abstract: We study the lepton forward-backward asymmetry AFB and the longitudinal K* polarization F-L, as well as an observable P-2 derived from them, in the rare decays B -> K*l(+)l(-), where l(+)l(-) is either e(+)e(-) or mu(+)mu(-), using the full sample of 471 million B (B) over bar events collected at the Upsilon(4S) resonance with the BABAR, detector at the PEP-II e(+)e(-) collider. We separately fit and report results for the K*(0)(892)l(+)l(-) and K*(+)(892) l(+)l(-) final states, as well as their combination K*l(+)l(-), in five disjoint dilepton mass-squared bins. An angular analysis of B+ -> K*(+)l(+)l(-) decays is presented here for the first time.
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Pich, A., Rosell, I., Santos, J., & Sanz-Cillero, J. J. (2016). Low-energy signals of strongly-coupled electroweak symmetry-breaking scenarios. Phys. Rev. D, 93(5), 055041–6pp.
Abstract: The nonobservation of new particles at the LHC suggests the existence of a mass gap above the electroweak scale. This situation is adequately described through a general electroweak effective theory with the established fields and Standard Model symmetries. Its couplings contain all information about the unknown short-distance dynamics which is accessible at low energies. We consider a generic strongly coupled scenario of electroweak symmetry breaking, with heavy states above the gap, and analyze the imprints that its lightest bosonic excitations leave on the effective Lagrangian couplings. Different quantum numbers of the heavy states imply different patterns of low-energy couplings, with characteristic correlations which could be identified in future data samples. The predictions can be sharpened with mild assumptions about the ultraviolet behaviour of the underlying fundamental theory.
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Xie, J. J., Liang, W. H., & Oset, E. (2016). (K)over-bar-induced formation of the f(0)(980) and a(0)(980) resonances on proton targets. Phys. Rev. C, 93(3), 035206–8pp.
Abstract: We perform a calculation of the cross section for nine reactions induced by (K) over bar scattering on protons. The reactions studied are K- p -> Lambda pi(+)pi(-), K- p -> Sigma(0)pi(+)pi(-), K- p -> Lambda pi(0)eta, K- p -> Sigma(0)pi(0)eta, K- p -> Sigma(+)pi(-)eta, (K) over bar (0) p -> Lambda pi(+)eta, (K) over bar (0) p -> Sigma(0)pi(+)eta, (K) over bar (0) p -> Sigma(+)pi(+)pi(-), and (K) over bar (0) p -> Sigma+pi(0)eta. We find that in the reactions producing pi(+)pi(-), a clear peak for the f(0)(980) resonance is found, while no trace of f(0)(500) appears. Similarly, in the cases of p. production, a strong peak is found for the a(0)(980) resonance, with the characteristic strong cusp shape. Cross sections and invariant mass distributions are evaluated which should serve, by comparing them with future data, to test the dynamics of the chiral unitary approach used for the evaluations and the nature of these resonances.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Measurements of prompt charm production cross-sections in pp collisions at root s=13 TeV. J. High Energy Phys., 03(3), 159–43pp.
Abstract: Production cross-sections of prompt charm mesons are measured with the first data from pp collisions at the LHC at a centre-of-mass energy of 13 TeV. The data sample corresponds to an integrated luminosity of 4.98 +/- 0.19 pb(-1) collected by the LHCb experiment. The production cross-sections of D-0, D+, D (s) (+) , and D*+ mesons are measured in bins of charm meson transverse momentum, p(T), and rapidity, y, and cover the range 0 < p(T) < 15GeV/c and 2.0 < y < 4.5. The inclusive cross-sections for the four mesons, including charge conjugation, within the range of 1 < p(T) < 8 GeV/c are found to be sigma(pp -> D-0 X) = 2460 +/- 3 +/- 130 μb sigma(pp -> D+ X) = 1000 +/- 3 +/- 110 μb sigma(pp -> Ds+X) = 460 +/- 13 +/- 100 μb sigma(pp -> D*+ X) = 880 +/- 5 +/- 140 μb where the uncertainties are due to statistical and systematic uncertainties, respectively.
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Huyuk, T. et al, Gadea, A., Aliaga-Varea, R. J., & Domingo-Pardo, C. (2016). Conceptual design of the early implementation of the NEutron Detector Array (NEDA) with AGATA. Eur. Phys. J. A, 52(3), 55–8pp.
Abstract: The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large gamma-ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23 l and it is filled with the EJ301 liquid scintillator, that presents good neutron-gamma discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the Ni-58 + Fe-56 reaction measured with the Neutron Wall detector array.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Study of psi(2S) production and cold nuclear matter effects in pPb collisions at root s(NN)=5 TeV. J. High Energy Phys., 03(3), 133–21pp.
Abstract: The production of psi(2S) mesons is studied in dimuon final states using proton-lead (pPb) collision data collected by the LHCb detector. The data sample corresponds to an integrated luminosity of 1.6 nb(-1). The nucleon-nucleon centre-of-mass energy of the pPb collisions is root s(NN) = 5 TeV. The measurement is performed using psi(2S) mesons with transverse momentum less than 14 GeV/c and rapidity y in the ranges 1.5 < y < 4.0 and -5.0 < y < -2.5 in the nucleon-nucleon centre-of-mass system. The forward-backward production ratio and the nuclear modi fi cation factor are determined for psi(2S) mesons. Using the production cross-section results of psi(2S) and J/psi mesons from b-hadron decays, the b (b) over bar cross-section in pPb collisions at root s(NN) = 5 TeV is obtained.
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Bergstrom, J., Gonzalez-Garcia, M. C., Maltoni, M., Pena-Garay, C., Serenelli, A. M., & Song, N. Q. (2016). Updated determination of the solar neutrino fluxes from solar neutrino data. J. High Energy Phys., 03(3), 132–19pp.
Abstract: We present an update of the determination of the solar neutrino fluxes from a global analysis of the solar and terrestrial neutrino data in the framework of three-neutrino mixing. Using a Bayesian analysis we reconstruct the posterior probability distribution function for the eight normalization parameters of the solar neutrino fluxes plus the relevant masses and mixing, with and without imposing the luminosity constraint. We then use these results to compare the description provided by different Standard Solar Models. Our results show that, at present, both models with low and high metallicity can describe the data with equivalent statistical agreement. We also argue that even with the present experimental precision the solar neutrino data have the potential to improve the accuracy of the solar model predictions.
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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fernandez Martinez, P., et al. (2016). Search for magnetic monopoles and stable particles with high electric charges in 8 TeV pp collisions with the ATLAS detector. Phys. Rev. D, 93(5), 052009–25pp.
Abstract: A search for highly ionizing particles produced in proton-proton collisions at 8 TeV center-of-mass energy is performed by the ATLAS Collaboration at the CERN Large Hadron Collider. The data set used corresponds to an integrated luminosity of 7.0 fb(-1). A customized trigger significantly increases the sensitivity, permitting a search for such particles with charges and energies beyond what was previously accessible. No events were found in the signal region, leading to production cross section upper limits in the mass range 200-2500 GeV for magnetic monopoles with magnetic charge in the range 0.5g(D) < vertical bar g vertical bar < 2.0g(D), where g(D) is the Dirac charge, and for stable particles with electric charge in the range 10 < vertical bar z vertical bar < 60. Model-dependent limits are presented in given pair-production scenarios, and model-independent limits are presented in fiducial regions of particle energy and pseudorapidity.
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