ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2017). Jet energy scale measurements and their systematic uncertainties in proton-proton collisions at root s=13 TeV with the ATLAS detector. Phys. Rev. D, 96(7), 072002–36pp.
Abstract: Jet energy scale measurements and their systematic uncertainties are reported for jets measured with the ATLAS detector using proton-proton collision data with a center-of-mass energy of root s = 13 TeV, corresponding to an integrated luminosity of 3.2 fb(-1) collected during 2015 at the LHC. Jets are reconstructed from energy deposits forming topological clusters of calorimeter cells, using the anti-k(t) algorithm with radius parameter R = 0.4. Jets are calibrated with a series of simulation-based corrections and in situ techniques. In situ techniques exploit the transverse momentum balance between a jet and a reference object such as a photon, Z boson, or multijet system for jets with 20 < p(T) < 2000 GeV and pseudorapidities of vertical bar eta vertical bar < 4.5, using both data and simulation. An uncertainty in the jet energy scale of less than 1% is found in the central calorimeter region (vertical bar eta vertical bar < 1.2) for jets with 100 < p(T) < 500 GeV. An uncertainty of about 4.5% is found for low-p(T) jets with p(T) = 20 GeV in the central region, dominated by uncertainties in the corrections for multiple proton-proton interactions. The calibration of forward jets (vertical bar eta vertical bar > 0.8) is derived from dijet p(T) balance measurements. For jets of p(T) = 80 GeV, the additional uncertainty for the forward jet calibration reaches its largest value of about 2% in the range vertical bar eta vertical bar > 3.5 and in a narrow slice of 2.2 < vertical bar eta vertical bar < 2.4.
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Sanchis-Lozano, M. A., & Sarkisyan-Grinbaum, E. (2017). Ridge effect and three-particle correlations. Phys. Rev. D, 96(7), 074012–13pp.
Abstract: Pseudorapidity and azimuthal three-particle correlations are studied based on a correlated-cluster model of multiparticle production. The model provides a common framework for correlations in proton-proton and heavy-ion collisions allowing easy comparison with the measurements. It is shown that azimuthal cluster correlations are definitely required in order to understand three-particle correlations in the near-side ridge effect. This is similar to the explanation of the ridge phenomenon found in our previous analysis of two-particle correlations and generalizes the model to higher-order correlations.
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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). Observation of the Xi(-)(b) -> J/psi Lambda K- decay. Phys. Lett. B, 772, 265–273.
Abstract: The observation of the decay Xi(-)(b)-> J/psi Lambda K- is reported, using a data sample corresponding to an integrated luminosity of 3 fb(-1), collected by the LHCb detector in pp collisions at centre-of-mass energies of 7 and 8 TeV. The production rate of Xi(-)(b) baryons detected in the decay Xi(-)(b) -> J/psi Lambda K- is measured relative to that of Lambda(0)(b) baryons using the decay Lambda(0)(b) -> J/psi Lambda. Integrated over the b-baryon transverse momentum p(T) < 25 GeV/c and rapidity 2.0 < y < 4.5, the measured ratio is f Xi(-)(b/) f Lambda(0)(b) B(Xi(-)(b)-> J/psi Lambda K-) / B(Lambda(0)(b)-> J/psi Lambda) = (4.19 +/- 0.29 (stat) +/- 0.15 (syst)) x 10(-2), where f(Xi)(b)(-) band f(Lambda)(b)(0)are the fragmentation fractions of b ->Xi(-)(b)and b ->Lambda(0)(b)transitions, and ss represents the branching fraction of the corresponding b- baryon decay. The mass difference between Xi(-)(b) and Lambda(0)(b) baryons is measured to be M(Xi(-)(b))-M(Lambda(0)(b)) = 177.08 +/- 0.47 (stat) +/- 0.16 (syst) MeV/c(2).
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Alves, A., Arcadi, G., Dong, P. V., Duarte, L., Queiroz, F. S., & Valle, J. W. F. (2017). Matter-parity as a residual gauge symmetry: Probing a theory of cosmological dark matter. Phys. Lett. B, 772, 825–831.
Abstract: We discuss a non-supersymmetric scenario which addresses the origin of the matter-parity symmetry, P-M = (-1)(3(B-L)+2s), leading to a viable Dirac fermion dark matter candidate. Implications to electroweak precision, muon anomalous magnetic moment, flavor changing interactions, lepton flavor violation, dark matter and collider physics are discussed in detail. We show that this non-supersymmetric model is capable of generating the matter-parity symmetry in agreement with existing data with gripping implications to particle physics and cosmology.
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Sakai, S., Oset, E., & Liang, W. H. (2017). Abnormal isospin violation and a(0) – f(0) mixing in the D-s(+) -> pi(+) pi(0)a(0)(980)(f(0)(980)) reactions. Phys. Rev. D, 96(7), 074025–11pp.
Abstract: We have chosen the reactions D-s(+) -> pi(+) pi(0)a(0)(980)(f(0)(980)) investigating the isospin violating channel D-s(+) -> pi+ pi(0)f(0)(980). The reaction was chosen because by varying the pi(0)a(0)(980)(f(0)(980)) invariant mass one goes through the peak of a triangle singularity emerging from D-s(+) -> pi(K) over bar *K, followed by (K) over bar* -> (K) over bar pi(0) and the further merging of K (K) over bar to produce the a(0)(980) or f(0)(980). We found that the amount of isospin violation had its peak precisely at the value of the pi(0)a(0)(980)(f(0)(980)) invariant mass where the singularity has its maximum, stressing the role of the triangle singularities as a factor to enhance the mixing of the f(0)(980) and a(0)(980) resonances. We calculate absolute rates for the reactions and show that they are within present measurable range. The measurement of these reactions would bring further information into the role of triangle singularities in isospin violation and the a(0) – f(0) mixing, in particular, and shed further light into the nature of the low energy scalar mesons.
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Becker, P., Davesne, D., Meyer, J., Navarro, J., & Pastore, A. (2017). Solution of Hartree-Fock-Bogoliubov equations and fitting procedure using the N2LO Skyrme pseudopotential in spherical symmetry. Phys. Rev. C, 96(4), 044330–17pp.
Abstract: We present the development of the extended Skyrme N2LO pseudopotential in the case of spherical even-even nuclei calculations. The energy density functional is first presented. Then we derive the mean-field equations and discuss the numerical method used to solve the resulting fourth-order differential equation together with the behavior of the solutions at the origin. Finally, a fitting procedure for such an N2LO interaction is discussed and we provide a first parametrization. Typical ground-state observables are calculated and compared against experimental data.
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Centelles Chulia, S., Srivastava, R., & Valle, J. W. F. (2017). Generalized bottom-tau unification, neutrino oscillations and dark matter: Predictions from a lepton quarticity flavor approach. Phys. Lett. B, 773, 26–33.
Abstract: We propose an A(4) extension of the Standard Model with a Lepton Quarticity symmetry correlating dark matter stability with the Dirac nature of neutrinos. The flavor symmetry predicts (i) a generalized bottom-tau mass relation involving all families, (ii) small neutrino masses are induced a la seesaw, (iii) CP must be significantly violated in neutrino oscillations, (iv) the atmospheric angle theta(23) lies in the second octant, and (v) only the normal neutrino mass ordering is realized.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2017). Measurement of the W+ W- production cross section in pp collisions at a centre-of-mass energy of root s=13 TeV with the ATLAS experiment. Phys. Lett. B, 773, 354–374.
Abstract: The production of opposite-charge W-boson pairs in proton-proton collisions at root s = 13 TeV is measured using data corresponding to 3.16 fb(-1) of integrated luminosity collected by the ATLAS detector at the CERN Large Hadron Collider in 2015. Candidate W-boson pairs are selected by identifying their leptonic decays into an electron, a muon and neutrinos. Events with reconstructed jets are not included in the candidate event sample. The cross-section measurement is performed in a fiducial phase space close to the experimental acceptance and is compared to theoretical predictions. Agreement is found between the measurement and the most accurate calculations available.
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Du, M. L., Guo, F. K., Meissner, U. G., & Yao, D. L. (2017). Study of open-charm 0(+) states in unitarized chiral effective theory with one-loop potentials. Eur. Phys. J. C, 77(11), 728–16pp.
Abstract: Chiral potentials are derived for the interactions between Goldstone bosons and pseudo-scalar charmed mesons up to next-to-next-to-leading order in a covariant chiral effective field theory with explicit vector charmed-meson degrees of freedom. Using the extended-on-mass-shell scheme, we demonstrate that the ultraviolet divergences and the so-called power counting breaking terms can be properly absorbed by the low-energy constants of the chiral Lagrangians. We calculate the scattering lengths by unitarizing the one-loop potentials and fit them to the data extracted from lattice QCD. The obtained results are compared to the ones without an explicit contribution of vector charmed mesons given previously. It is found that the difference is negligible for 5-wave scattering in the threshold region. This validates the use of D-*-less one-loop potentials in the study of the pertinent scattering lengths. We search for dynamically generated open-charm states with J(P) = 0(+) as poles of the 5-matrix on various Riemann sheets. The trajectories of those poles for varying pion masses are presented as well.
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Doncel, M., Gadea, A., Valiente-Dobon, J. J., Quintana, B., Modamio, V., Mengoni, D., et al. (2017). Determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method in combination with magnetic spectrometers. Eur. Phys. J. A, 53(10), 211–5pp.
Abstract: The current work presents the determination of lifetimes of nuclear excited states using the Recoil Distance Doppler Shift Method, in combination with spectrometers for ion identification, normalizing the intensity of the peaks by the ions detected in the spectrometer as a valid technique that produces results comparable to the ones obtained by the conventional shifted-to-unsifted peak ratio method. The technique has been validated using data measured with the gamma-ray array AGATA, the PRISMA spectrometer and the Cologne plunger setup. In this paper a test performed with the AGATA-PRISMA setup at LNL and the advantages of this new approach with respect to the conventional Recoil Distance Doppler Shift Method are discussed.
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