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Abdesselam, A. et al, Vos, M., & Fassi, F. (2011). Boosted objects: a probe of beyond the standard model physics. Eur. Phys. J. C, 71(6), 1661–19pp.
Abstract: We present the report of the hadronic working group of the BOOST2010 workshop held at the University of Oxford in June 2010. The first part contains a review of the potential of hadronic decays of highly boosted particles as an aid for discovery at the LHC and a discussion of the status of tools developed to meet the challenge of reconstructing and isolating these topologies. In the second part, we present new results comparing the performance of jet grooming techniques and top tagging algorithms on a common set of benchmark channels. We also study the sensitivity of jet substructure observables to the uncertainties in Monte Carlo predictions.
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Coloma, P., Donini, A., Migliozzi, P., Lavina, L. S., & Terranova, F. (2011). A minimal Beta Beam with high-Q ions to address CP violation in the leptonic sector. Eur. Phys. J. C, 71(6), 1674–11pp.
Abstract: In this paper we consider a Beta Beam setup that tries to leverage at most existing European facilities: i.e. a setup that takes advantage of facilities at CERN to boost high-Q ions ((8)Li and (8)B) aiming at a far detector located at L = 732 km in the Gran Sasso Underground Laboratory. The average neutrino energy for (8)Li and (8)B ions boosted at gamma similar to 100 is in the range E(nu) is an element of [1, 2] GeV, high enough to use a large iron detector of the MINOS type at the far site. We perform, then, a study of the neutrino and antineutrino fluxes needed to measure a CP-violating phase delta in a significant part of the parameter space. In particular, for theta(13) >= 3 degrees, if an antineutrino flux of 3 x 10(19) useful (8)Li decays per year is achievable, we find that delta can be measured in 60% of the parameter space with 3 x 10(18) useful (8)B decays per year.
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ATLAS Collaboration(Aad, G. et al), Amoros, G., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Escobar, C., et al. (2012). Performance of missing transverse momentum reconstruction in proton-proton collisions at root s=7 TeV with ATLAS. Eur. Phys. J. C, 72(1), 1844–35pp.
Abstract: The measurement of missing transverse momentum in the ATLAS detector, described in this paper, makes use of the full event reconstruction and a calibration based on reconstructed physics objects. The performance of the missing transverse momentum reconstruction is evaluated using data collected in pp collisions at a centre-of-mass energy of 7 TeV in 2010. Minimum bias events and events with jets of hadrons are used from data samples corresponding to an integrated luminosity of about 0.3 nb(-1) and 600 nb(-1) respectively, together with events containing a Z boson decaying to two leptons (electrons or muons) or a W boson decaying to a lepton (electron or muon) and a neutrino, from a data sample corresponding to an integrated luminosity of about 36 pb(-1). An estimate of the systematic uncertainty on the missing transverse momentum scale is presented.
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ATLAS Collaboration(Aad, G. et al), Amoros, G., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Escobar, C., et al. (2012). Performance of the ATLAS Trigger System in 2010. Eur. Phys. J. C, 72(1), 1849–61pp.
Abstract: Proton-proton collisions at root s = 7 TeV and heavy ion collisions at root(NN)-N-s = 2.76 TeV were produced by the LHC and recorded using the ATLAS experiment's trigger system in 2010. The LHC is designed with a maximum bunch crossing rate of 40 MHz and the ATLAS trigger system is designed to record approximately 200 of these per second. The trigger system selects events by rapidly identifying signatures of muon, electron, photon, tau lepton, jet, and B meson candidates, as well as using global event signatures, such as missing transverse energy. An overview of the ATLAS trigger system, the evolution of the system during 2010 and the performance of the trigger system components and selections based on the 2010 collision data are shown. A brief outline of plans for the trigger system in 2011 is presented.
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Cappiello, L., Cata, O., D'Ambrosio, G., & Gao, D. N. (2012). K+ -> pi(+) pi(0)e(+) e(-): a novel short-distance probe. Eur. Phys. J. C, 72(1), 1872–16pp.
Abstract: We study the decay K+ -> pi(+) pi(0)e(+) e(-), currently under analysis by the NA62 Collaboration at CERN. In particular, we provide a detailed analysis of the Dalitz plot for the long-distance, gamma*-mediated, contributions (Brems-strahlung, direct emission and its interference). We also examine a set of asymmetries to isolate genuine short-distance effects. While we show that charge asymmetries are not required to test short distances, they provide the best environment for its detection. This constitutes by itself a strong motivation for NA62 to study K- decays in the future. We therefore provide a detailed study of different charge asymmetries and the corresponding estimated signals. Whenever possible, we make contact with the related processes K+ -> pi(+) pi(0)gamma and K-L -> pi(+) pi(0)e(+) e(-) and discuss the advantages of K+ -> pi(+) pi(0)e(+) e(-) over them.
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