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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2013). Measurement of the high-mass Drell-Yan differential cross-section in pp collisions at root s=7 TeV with the ATLAS detector. Phys. Lett. B, 725(4-5), 223–242.
Abstract: This Letter reports a measurement of the high-mass Drell-Yan differential cross-section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC. Based on an integrated luminosity of 4.9 fb(-1), the differential cross-section in the Z/gamma* -> e(+)e(-) channel is measured with the ATLAS detector as a function of the invariant mass, m(ee), in the range 116 < m(ee) < 1500 GeV, for a fiducial region in which both the electron and the positron have transverse momentum p(T) > 25 GeV and pseudorapidity vertical bar n vertical bar < 2.5. A comparison is made to various event generators and to the predictions of perturbative QCD calculations at next-to-next-to-leading order.
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Gottardo, A. et al, Gadea, A., & Algora, A. (2013). New μs isomers in the neutron-rich Hg-210 nucleus. Phys. Lett. B, 725(4-5), 292–296.
Abstract: Neutron-rich nuclei in the lead region, beyond N = 126, have been studied at the FRS-RISING setup at GSI, exploiting the fragmentation of a primary uranium beam. Two isomeric states have been identified in Hg-210: the 8(+) isomer expected from the seniority scheme in the vg(9/2) shell and a second one at low spin and low excitation energy. The decay strength of the 8(+) isomer confirms the need of effective three-body forces in the case of neutron-rich lead isotopes. The other unexpected low-lying isomer has been tentatively assigned as a 3(-) state, although this is in contrast with theoretical expectations.
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Das, C. R., Mena, O., Palomares-Ruiz, S., & Pascoli, S. (2013). Determining the dark matter mass with DeepCore. Phys. Lett. B, 725(4-5), 297–301.
Abstract: Cosmological and astrophysical observations provide increasing evidence of the existence of dark matter in our Universe. Dark matter particles with a mass above a few GeV can be captured by the Sun, accumulate in the core, annihilate, and produce high energy neutrinos either directly or by subsequent decays of Standard Model particles. We investigate the prospects for indirect dark matter detection in the IceCube/DeepCore neutrino telescope and its capabilities to determine the dark matter mass.
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del Aguila, F., Chala, M., Santamaria, A., & Wudka, J. (2013). Discriminating between lepton number violating scalars using events with four and three charged leptons at the LHC. Phys. Lett. B, 725(4-5), 310–315.
Abstract: Many Standard Model extensions predict doubly-charged scalars; in particular, all models with resonances in charged lepton-pair channels with non-vanishing lepton number; if these are pair produced at the LHC, the observation of their decay into l(-/+)l(-/+)W(-/+)W(-/+) will be necessary in order to establish their lepton-number violating character, which is generally not straightforward. Nonetheless, the analysis of events containing four charged leptons (including scalar decays into one or two taus as well as into W bosons) makes it possible to determine whether the doubly-charged excitation belongs to a multiplet with weak isospin T = 0,1/2,1,3/2 or 2 (assuming there are no excitations with charge > 2); though discriminating between the isosinglet and isodoublet cases is possible only if charged-current events cannot produce the doubly-charged isosinglet.
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Serodio, H. (2013). Yukawa sector of multi-Higgs-doublet models in the presence of Abelian symmetries. Phys. Rev. D, 88(5), 056015–48pp.
Abstract: A general method for classifying the possible quark models of a multi-Higgs-doublet model, in the presence of Abelian symmetries, is presented. All the possible sets of textures that can be present in a given sector are shown, thus turning the determination of the flavor models into a combinatorial problem. Several symmetry implementations are studied for two and three Higgs doublet models. Some models' implementations are explored in great detail, with a particular emphasis on models known as Branco-Grimus-Lavoura and nearest-neighbor-interaction. Several considerations on the flavor changing neutral currents of multi-Higgs models are also given.
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Giusarma, E., de Putter, R., Ho, S., & Mena, O. (2013). Constraints on neutrino masses from Planck and Galaxy clustering data. Phys. Rev. D, 88(6), 063515–9pp.
Abstract: We present here bounds on neutrino masses from the combination of recent Planck cosmic microwave background (CMB) measurements and galaxy clustering information from the Baryon Oscillation Spectroscopic Survey, part of the Sloan Digital Sky Survey-III. We use the full shape of either the photometric angular clustering (Data Release 8) or the 3D spectroscopic clustering (Data Release 9) power spectrum in different cosmological scenarios. In the Lambda CDM scenario, spectroscopic galaxy clustering measurements improve significantly the existing neutrino mass bounds from Planck data. We find Sigma m(v) < 0.39 eV at 95% confidence level for the combination of the 3D power spectrum with Planck CMB data (wi lensing included) and Wilkinson Microwave Anisoptropy Probe 9-year polarization measurements. Therefore, robust neutrino mass constraints can be obtained without the addition of the prior on the Hubble constant from Hubble Space Telescope. In extended cosmological scenarios with a dark energy fluid or with nonflat geometries, galaxy clustering measurements are essential to pin down the neutrino mass bounds, providing in the majority of cases better results than those obtained from the associated measurement of the baryon acoustic oscillation scale only. In the presence of a freely varying (constant) dark energy equation of state, we find Sigma m(v) < 0.49 eV at 95% confidence level for the combination of the 3D power spectrum with Planck CMB data (with lensing included) and Wilkinson Microwave Anisoptropy Probe 9-year polarization measurements. This same data combination in nonflat geometries provides the neutrino mass bound Sigma m(v) < 0.35 eV at 95% confidence level.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2013). Search for excited electrons and muons in root s=8 TeV proton-proton collisions with the ATLAS detector. New J. Phys., 15, 093011–32pp.
Abstract: The ATLAS detector at the Large Hadron Collider is used to search for excited electrons and excited muons in the channel pp -> ll* -> ll gamma, assuming that excited leptons are produced via contact interactions. The analysis is based on 13 fb(-1) of pp collisions at a centre-of-mass energy of 8 TeV. No evidence for excited leptons is found, and a limit is set at the 95% credibility level on the cross section times branching ratio as a function of the excited-lepton mass m(l*). For m(l*) >= 0.8 TeV, the respective upper limits on sigma B(l(*) -> l gamma) are 0.75 and 0.90 fb for the e* and mu* searches. Limits on sigma B are converted into lower bounds on the compositeness scale 3. In the special case where Lambda = m(l*), excited-electron and excited-muon masses below 2.2 TeV are excluded.
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Hellmann, C., & Ruiz-Femenia, P. (2013). Non-relativistic pair annihilation of nearly mass degenerate neutralinos and charginos II. P-wave and next-to-next-to-leading order S-wave coefficients. J. High Energy Phys., 08(8), 084–49pp.
Abstract: This paper is a continuation of an earlier work (arXiv:1210.7928) which computed analytically the tree-level annihilation rates of a collection of non-relativistic neutralino and chargino two-particle states in the general MSSM. Here we extend the results by providing the next-to-next-to-leading order corrections to the rates in the non-relativistic expansion in momenta and mass differences, which include leading P-wave effects, in analytic form. The results are a necessary input for the calculation of the Sommerfeld-enhanced dark matter annihilation rates including short-distance corrections at next-to-next-to-leading order in the non-relativistic expansion in the general MSSM with neutralino LSP.
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Lattanzi, M., Riemer-Sorensen, S., Tortola, M., & Valle, J. W. F. (2013). Updated CMB and x- and gamma-ray constraints on Majoron dark matter. Phys. Rev. D, 88(6), 063528–8pp.
Abstract: The Majoron provides an attractive dark matter candidate, directly associated with the mechanism responsible for spontaneous neutrino mass generation within the standard model SU(3)(c) circle times SU(2)(L) circle times U(1)(Y) framework. Here we update the cosmological and astrophysical constraints on Majoron dark matter coming from the cosmic microwave background and a variety of x- and gamma-ray observations.
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Martinez Torres, A., Khemchandani, K. P., Jido, D., Kanada-En'yo, Y., & Oset, E. (2013). Three-body hadron systems with strangeness. Nucl. Phys. A, 914, 280–288.
Abstract: Recently, many efforts are being put in studying three-hadron systems made of mesons and baryons and interesting results are being found. In this talk, we summarize the main features of the formalism used to study such three hadron systems with strangeness S = -1, 0 within a framework built on the basis of unitary chiral theories and solution of the Faddeev equations. In particular, we present the results obtained for the pi(K) over barN, K (K) over barN and KK (K) over bar systems and their respective coupled channels. In the first case, we find four Sigma's and two A's with spin-parity J(P) = 1/2(+), in the 1500-1800 MeV region, as two meson-one baryon s-wave resonances. In the second case, a 1/2(+) N* around 1900 MeV is found. For the last one a kaon close to 1420 MeV is formed, which can be identified with K(1460).
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