European Physical Journal C (EUR PHYS J C)

Publications in this journal

• Article: Structural and magnetic phase transitions in Pr0.15Sr0.85MnO3 at high pressure

  D.P. Kozlenko, N.T. Dang, Z. Jirak, S.E. Kichanov, E.V. Lukin, B.N. Savenko, L.S. Dubrovinsky, C. Lathe, C Martin
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  ABSTRACT: Journal article
  European Physical Journal C 05/2013; 77:407.
• Article: High voltage capacitors for low background experiments

  C. O’Shaughnessy, E. Andreotti, D. Budjáš, A. Caldwell, A. Gangapshev, K. Gusev, M. Hult, A. Lubashevskiy, B. Majorovits, S. Schönert, A. Smolnikov
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  ABSTRACT: Low background experiments place stringent constraints on amount of radioactive impurities in the materials used for their assembly. Often these are in conflict with the constraints placed on the materials by their roles in the experiment. This is especially true for certain electronic components. A high value, high voltage capacitor for use in low background experiments has been developed from specially selected radiopure materials. Electroformed copper foils are separated by polyethylene napthalate (PEN) foils and supported within a PTFE teflon spiral coil tube. The electrical performance as well as radiopurity are scrutinized here. With some minor modifications to tune the performance for the application, this capacitor can be well suited for a variety of applications in low background experiments. Here the use of the capacitor for high voltage (HV) decoupling in the operation of high purity germanium (HPGe) detectors is demonstrated.
  European Physical Journal C 05/2013;
• Article: Experimental search for the LSND anomaly with the ICARUS detector in the CNGS neutrino beam

  M. Antonello, B. Baibussinov, P. Benetti, E. Calligarich, N. Canci, S. Centro, A. Cesana, K. Cieslik, D. B. Cline, A. G. Cocco, [......], R. Sulej, M. Szarska, M. Terrani, F. Varanini, S. Ventura, C. Vignoli, H. Wang, X. Yang, A. Zalewska, K. Zaremba
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  ABSTRACT: We report an early result from the ICARUS experiment on the search for nu_mu to nu_e signal due to the LSND anomaly. The search was performed with the ICARUS T600 detector located at the Gran Sasso Laboratory, receiving CNGS neutrinos from CERN at an average energy of about 20 GeV, after a flight path of about 730 km. The LSND anomaly would manifest as an excess of nu_e events, characterized by a fast energy oscillation averaging approximately to sin^2(1.27 Dm^2_new L/ E_nu) = 1/2. The present analysis is based on 1091 neutrino events, which are about 50% of the ICARUS data collected in 2010-2011. Two clear nu_e events have been found, compared with the expectation of 3.7 +/- 0.6 events from conventional sources. Within the range of our observations, this result is compatible with the absence of a LSND anomaly. At 90% and 99% confidence levels the limits of 3.4 and 7.3 events corresponding to oscillation probabilities of 5.4 10^-3 and 1.1 10^-2 are set respectively. The result strongly limits the window of open options for the LSND anomaly to a narrow region around (Dm^2, sin^2(2 theta))_new = (0.5 eV^2, 0.005), where there is an overall agreement (90% CL) between the present ICARUS limit, the published limits of KARMEN and the published positive signals of LSND and MiniBooNE Collaborations.
  European Physical Journal C 03/2013; 73:2345.
• Article: D* and D Meson Production in Muon Nucleon Interactions at 160 GeV/c

  C. Adolph, M. G. Alekseev, V. Yu. Alexakhin, Yu. Alexandrov, G. D. Alexeev, A. Amoroso, A. A. Antonov, A. Austregesilo, B. Badelek, F. Balestra, [......], M. Wilfert, R. Windmolders, W. Wislicki, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, M. Ziembicki, N. Zhuravlev, A. Zvyagin
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  ABSTRACT: The production of D* and D mesons in inelastic scattering of 160 GeV/c muons off a ^6LiD target has been investigated with the COMPASS spectrometer at CERN for 0.003 (GeV/c)^2 < Q^2 < 10 (GeV/c)^2 and 3x10^-5< x_Bj < 0.1. The study is based on 8100 events where a D^0 or anti D^0 is detected subsequently to a D*+ or D*- decay, and on 34000 events, where only a D^0 or anti D^0 is detected. Kinematic distributions of D*, D and K*_2 are given as a function of their energy E, transverse momentum p_T, energy fraction z, and of the virtual photon variables nu, Q^2 and x_Bj. Semi-inclusive differential D* production cross-sections are compared with theoretical predictions for D* production via photon-gluon fusion into open charm. The total observed production cross-section for D*+/- mesons with laboratory energies between 22 and 86 GeV is 1.9 nb. Significant cross-section asymmetries are observed between D*+ and D*- production for nu<40 GeV and z>0.6.
  European Physical Journal C 11/2012; 72(12).
• Article: Dark matter, matter creation and curvature

  Victor H. Cardenas
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  ABSTRACT: The most studied way to explain the current accelerated expansion of the universe is to assume the existence of dark energy; a new component that fill the universe, does not clumps, currently dominates the evolution, and has a negative pressure. In this work I study an alternative model proposed by Lima et al. \cite{lima96}, which does not need an exotic equation of state, but assumes instead the existence of gravitational particle creation. Because this model fits the supernova observations as well as the $\Lambda$CDM model, I perform in this work a thorough study of this model considering an explicit spatial curvature. I found that in this scenario we can alleviate the cosmic coincidence problem, basically showing that these two components, dark matter and dark energy, are of the same nature, but they act at different scales. I also shown the inadequacy of some particle creation models, and also I study a previously propose new model that overcome these difficulties.
  European Physical Journal C 09/2012; 72(9):2149.
• Article: Hamiltonian dynamics and Noether symmetries in Extended GravityCosmology

  Salvatore Capozziello, Mariafelicia De Laurentis, Sergei D. Odintsov
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  ABSTRACT: We discuss the Hamiltonian dynamics for cosmologies coming from Extended Theories of Gravity. In particular, minisuperspace models are taken into account searching for Noether symmetries. The existence of conserved quantities gives selection rule to recover classical behaviors in cosmic evolution according to the so called Hartle criterion, that allows to select correlated regions in the configuration space of dynamical variables. We show that such a statement works for general classes of Extended Theories of Gravity and is conformally preserved. Furthermore, the presence of Noether symmetries allows a straightforward classification of singularities that represent the points where the symmetry is broken. Examples of nonminimally coupled and higher-order models are discussed.
  European Physical Journal C 06/2012; 27:72.
• Article: W boson inclusive decays to quarkonium and meson at the LHC

  Cong-Feng Qiao, Li-Ping Sun, De-Shan Yang, Rui-Lin Zhu
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  ABSTRACT: In this paper, the production rates of quarkonia η c , J/ψ, η b , ϒ and Bc(*)B_{c}^{(*)} mesons through W + boson decay at the LHC are calculated, at the leading order in both the QCD coupling α s and in v, the typical velocity of the heavy quark inside mesons. It shows that a sizable number of quarkonia and Bc(*)B_{c}^{(*)} mesons from W + boson decay will be produced at the LHC. Comparison with the predictions by using quark fragmentation mechanism is also discussed. Results show that, for the charmonium production through W + decay, the difference between predictions by the fragmentation mechanism and complete leading order calculation is around 3%, and it is insensitive to the uncertainties of theoretical parameters; however, for the bottomonium and Bc(*)B_{c}^{(*)} productions, the difference cannot be ignored as the fragmentation mechanism is less applicable here due to the relatively large ratio m b /m w .
  European Physical Journal C 05/2012; 71(10):1-14.
• Article: Exploring CP violation and η–η′ mixing with the systems

  Robert Fleischer, Robert Knegjens, Giulia Ricciardi
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  ABSTRACT: The B0s,d ® J/yh(¢)B^{0}_{s,d} \to J/\psi \eta^{(\prime)} decays provide new terrain for exploring CP violation. After briefly discussing η–η′ mixing, we analyse the effective lifetimes and CP-violating observables of the B s channels, which allow us to probe New-Physics effects in B0sB^{0}_{s}–[`(B)]0s\bar{B}^{0}_{s} mixing. We have a critical look at these observables and show how hadronic corrections can be controlled by means of the B d decays. Using measurements of the B0s,d® J/yh(¢)B^{0}_{s,d}\to J/\psi \eta^{(\prime)} branching ratios by the Belle collaboration, we discuss tests of the SU(3)F flavour symmetry of strong interactions, obtain the first constraints on the hadronic parameters entering the B0s,d ® J/yhB^{0}_{s,d} \to J/\psi \eta system, and predict the B0d® J/yh¢B^{0}_{d}\to J/\psi \eta' branching ratio at the 5×10−6 level. Furthermore, we present strategies for the determination of the η–η′ mixing parameters from the B0s,d ® J/yh(¢)B^{0}_{s,d} \to J/\psi \eta^{(\prime)} observables. We also observe that the B0s,d ® J/yhB^{0}_{s,d} \to J/\psi \eta and B0s,d ® J/yh¢B^{0}_{s,d} \to J/\psi \eta' decays are—from a formal point of view—analogous to the quark–antiquark and tetraquark descriptions of the f 0(980) in the B0s,d ® J/yf0(980)B^{0}_{s,d} \to J/\psi f_{0}(980) channels, respectively.
  European Physical Journal C 05/2012; 71(11):1-10.
• Article: A holographic energy model

  Peng Huang, Yong-Chang Huang
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  ABSTRACT: We suggest a holographic energy model in which the energy coming from spatial curvature, matter and radiation can be obtained by using the particle horizon for the infrared cut-off. We show the consistency between the holographic dark-energy model and the holographic energy model proposed in this paper. Then, we give a holographic description of the universe.
  European Physical Journal C 05/2012; 69(3):503-507.
• Source

  Available from: cdsweb.cern.ch

  Article: Trigger and reconstruction for heavy long-lived charged particles with the ATLAS detector

  S. Tarem, S. Bressler, H. Nomoto, A. Di Mattia
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  ABSTRACT: Long lived charged particles are predicted by many models of physics beyond the standard model (SM). The common signature of such models is a heavy long-lived charged particle with velocity smaller than the speed of light, β<1. This unique signature makes the search for it model independent. This paper presents methods we developed as part of the ATLAS trigger and reconstruction chain for identifying slow particles and measuring their mass. The efficacy of these methods is demonstrated using two models that are different in every aspect except for the existence of long lived charged particles; a GMSB model that includes sleptons with a mass of 100 GeV, and R-Hadrons with a mass of 300 GeV produced in a split SUSY model.
  European Physical Journal C 05/2012; 62(2):281-292.
• Article: Abelian decomposition method for G2 gauge theory

  W.-C. Su
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  ABSTRACT: The method of Abelian decomposition proposed by Faddeev and Niemi is used to derive the low-energy effective lagrangian of G2 gauge theory. The G2 algebra is studied. The commutation relations among the generators of the G2 algebra are established, based on the framework of its regular maximal subalgebra, an SU(3) algebra.
  European Physical Journal C 05/2012; 28(1):147-150.
• Article: Path integral for a Dirac particle in a quantized plane wave field

  B. Bentag, A. Merdaci, L. Chetouani
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  ABSTRACT: The problem of a relativistic spinning particle interacting with a quantized electromagnetic plane wave is treated by employing path integral methods and introducing the notion of a coherent state action. The dynamics of the particle spin is described using the supersymmetric action proposed recently by Alexandrou et al. in the so-called global representation. It is shown that to obtain the relative causal Green function, two fermionic identities, related directly to the classical equations of motion, have to be incorporated. The Green function, as constructed, allows us to extract in a natural way the expressions of the corresponding energy spectrum and wave functions.
  European Physical Journal C 05/2012; 26(2):311-320.
• Article: Analysis of the lepton polarisation asymmetries of decay

  S. R. Choudhury, A. S. Cornell, J. D. Roussos
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  ABSTRACT: In this work we will study the longitudinal polarisations of both leptons in the decay process [`(B)] ® [`(K)]2(1430) l+ l-{\bar{B}} \to {\bar{K}}_{2}(1430) \ell^{+} \ell^{-}. This process has all the features of the related and well investigated process [`(B)] ® [`(K)]*(890) l+ l-{\bar{B}} \to {\bar{K}}^{*}(890) \ell^{+} \ell^{-}, with theoretically comparable branching ratios. The polarised differential decay rates as well as the single and double polarisation asymmetries are worked out, where the sensitivity of these to possible right-handed couplings for the related b→s radiative decay (and other BSM parameters) are also investigated.
  European Physical Journal C 05/2012; 71(9):1-8.
• Article: Minimal supersymmetric technicolor

  Matti Antola, Stefano Di Chiara, Francesco Sannino, Kimmo Tuominen
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  ABSTRACT: We introduce novel extensions of the Standard Model featuring a supersymmetric technicolor sector. First we consider N=4\mathcal{N}=4 Super Yang–Mills which breaks to N=1\mathcal{N}=1 via the electroweak (EW) interactions and coupling to the MSSM. This is a well defined, economical and calculable extension of the SM involving the smallest number of fields. It constitutes an explicit example of a natural supersymmetric conformal extension of the Standard Model featuring a well defined connection to string theory. It allows us to interpolate, depending on how we break the underlying supersymmetry, between unparticle physics and Minimal Walking Technicolor. As a second alternative we consider other N = 1\mathcal{N} =1 extensions of the Minimal Walking Technicolor model. The new models allow all the standard model matter fields to acquire a mass.
  European Physical Journal C 05/2012; 71(11):1-13.