ANTARES Collaboration(Ageron, M. et al), Aguilar, J. A., Bigongiari, C., Carmona, E., Dornic, D., Emanuele, U., et al. (2011). ANTARES: The first undersea neutrino telescope. Nucl. Instrum. Methods Phys. Res. A, 656(1), 11–38.
Abstract: The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given.
|
ATLAS Collaboration(Aad, G. et al), Amoros, G., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Escobar, C., et al. (2011). Limits on the production of the standard model Higgs boson in pp collisions at sqrt(s)=7 TeV with the ATLAS detector. Eur. Phys. J. C, 71(9), 1728–30pp.
Abstract: A search for the Standard Model Higgs boson at the Large Hadron Collider (LHC) running at a centre-of-mass energy of 7 TeV is reported, based on a total integrated luminosity of up to 40 pb(-1) collected by the ATLAS detector in 2010. Several Higgs boson decay channels: H -> gamma gamma, H -> ZZ(()*()) -> llll, H -> ZZ -> LL nu nu, H -> ZZ -> llqq, H -> WW(()*()) -> l nu l nu and H -> WW -> l nu qq (l is e, mu) are combined in a mass range from 110 GeV to 600 GeV. The highest sensitivity is achieved in the mass range between 160 GeV and 170 GeV, where the expected 95% CL exclusion sensitivity is at Higgs boson production cross sections 2.3 times the Standard Model prediction. Upper limits on the cross section for its production are determined. Models with a fourth generation of heavy leptons and quarks with Standard Model-like couplings to the Higgs boson are also investigated and are excluded at 95% CL for a Higgs boson mass in the range from 140 GeV to 185 GeV.
|
Perez-Ramos, R., Mathieu, V., & Sanchis-Lozano, M. A. (2011). Three-particle correlations in QCD jets and beyond. J. Phys. G, 38(11), 115007–34pp.
Abstract: In this paper, we present a detailed study of three-particle correlations in quark and gluon jets. We give theoretical results for this observable in the double logarithmic approximation and the modified leading logarithmic approximation. In both resummation schemes, we use the formalism of the generating functional and solve the evolution equations analytically from the steepest descent evaluation of the one-particle distribution. In addition, in this paper we include predictions beyond the limiting spectrum approximation and study this observable near the hump of the single inclusive distribution. We thus provide a further test of the local parton hadron duality and make predictions for the LHC. The computation of higher rank correlators is presented in the double logarithmic approximation and shown to be rather cumbersome.
|
Beltrame, P. et al, Oliver, J. F., Rafecas, M., & Solevi, P. (2011). The AX-PET demonstrator-Design, construction and characterization. Nucl. Instrum. Methods Phys. Res. A, 654(1), 546–559.
Abstract: Axial PET is a novel geometrical concept for Positron Emission Tomography (PET), based on layers of long scintillating crystals axially aligned with the bore axis. The axial coordinate is obtained from arrays of wavelength shifting (WLS) plastic strips placed orthogonally to the crystals. This article describes the design, construction and performance evaluation of a demonstrator set-up which consists of two identical detector modules, used in coincidence. Each module comprises 48 LYSO crystals of 100 mm length and 156 WLS strips. Crystals and strips are readout by Geiger-mode Avalanche Photo Diodes (G-APDs). The signals from the two modules are processed by fully analog front-end electronics and recorded in coincidence by a VME-based data acquisition system. Measurements with point-like (22)Na sources, with the modules used both individually and in coincidence mode, allowed for a complete performance evaluation up to the focal plane reconstruction of point sources. The results obtained are in good agreement with expectations and proved the set-up to be ready for the next evaluation phase with PET phantoms filled with radiotracers.
|
AGATA and PRISMA Collaborations(Gadea, A. et al). (2011). Conceptual design and infrastructure for the installation of the first AGATA sub-array at LNL. Nucl. Instrum. Methods Phys. Res. A, 654(1), 88–96.
Abstract: The first implementation of the AGATA spectrometer consisting of five triple germanium detector clusters has been installed at Laboratori Nazionali di Legnaro, INFN. This setup has two major goals, the first one is to validate the gamma-tracking concept and the second is to perform an experimental physics program using the stable beams delivered by the Tandem-PIAVE-ALPI accelerator complex. A large variety of physics topics will be addressed during this campaign, aiming to investigate both neutron and proton-rich nuclei. The setup has been designed to be coupled with the large-acceptance magnetic-spectrometer PRISMA. Therefore, the in-beam prompt gamma rays detected with AGATA will be measured in coincidence with the products of multinucleon-transfer and deep-inelastic reactions measured by PRISMA. Moreover, the setup is versatile enough to host ancillary detectors, including the heavy-ion detector DANTE, the gamma-ray detector array HELENA, the Cologne plunger for lifetime measurements and the Si-pad telescope TRACE. In this paper the design; characteristics and performance figures of the setup will be described.
|
Ikeno, N., Yamagata-Sekihara, J., Nagahiro, H., Jido, D., & Hirenzaki, S. (2011). Formation of heavy-meson bound states by two-nucleon pick-up reactions. Phys. Rev. C, 84(5), 054609–7pp.
Abstract: We develop a model to evaluate the formation rate of the heavy mesic nuclei in two-nucleon pick-up reactions and apply it to the (6)Li target cases for the formation of heavy meson-alpha bound states, as examples. The existence of the quasideuteron in the target nucleus is assumed in this model. It is found that mesic nuclei formation in recoilless kinematics is possible even for heavier mesons than the nucleon in two-nucleon pick-up reactions. We find the formation rate of the meson-alpha bound states can be around half of the elementary cross sections at the recoilless kinematics with small distortions.
|
Steer, S. J. et al, & Estevez, M. E. (2011). Isomeric states observed in heavy neutron-rich nuclei populated in the fragmentation of a (208)Pb beam. Phys. Rev. C, 84(4), 044313–22pp.
Abstract: Heavy neutron-rich nuclei were populated via the fragmentation of a E/A = 1 GeV (208)(82)Pb beam. Secondary fragments were separated and identified and subsequently implanted in a passive stopper. By the detection of delayed gamma rays, isomeric decays associated with these nuclei have been identified. A total of 49 isomers were detected, with the majority of them observed for the first time. The newly discovered isomers are in (204,205)(80)Hg, (201,202,204,205)(79)Au, (197,203,204)(78)Pt, (195,199-203)(77)Ir, (193,197-199)(76)Os, (196)(75)Re, (190,191)(74)W, and (189)(73)Ta. Possible level schemes are constructed and the structure of the nuclei discussed. To aid the interpretation, shell-model as well as BCS calculations were performed.
|
CDF Collaboration(Aaltonen, T. et al), & Cabrera, S. (2011). Observation of the Baryonic Flavor-Changing Neutral Current Decay Lambda(0)(b) -> Lambda mu(+)mu(-). Phys. Rev. Lett., 107(20), 201802–8pp.
Abstract: We report the first observation of the baryonic flavor-changing neutral current decay Lambda(0)(b) -> Lambda mu(+)mu(-) with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses a p (p) over bar collisions data sample corresponding to 6.8 fb(-1) at root s = 1.96 TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Lambda(0)(b) -> Lambda mu(+)mu(-) are measured. We find B(Lambda(0)(b) -> Lambda mu(+)mu(-)) = [1.73 +/- 0.42(stat) +/- (syst)] x 10(-6). We also report the first measurement of the differential branching ratio of B(s)(0) -> phi mu(+)mu(-), using 49 signal events. In addition, we report branching ratios for B(+) -> K(+)mu(+)mu(-), B(0) -> K(0)mu(+)mu(-), and B -> K*(892)mu(+)mu(-) decays.
|
Borexino Collaboration(Bellini, G. et al), & Pena-Garay, C. (2011). Precision Measurement of the (7)Be Solar Neutrino Interaction Rate in Borexino. Phys. Rev. Lett., 107(14), 141302–5pp.
Abstract: The rate of neutrino-electron elastic scattering interactions from 862 keV (7)Be solar neutrinos in Borexino is determined to be 46.0 +/- 1.5(stat)(-1.6)(+1.5)(syst)counts/(day . 100 ton). This corresponds to a nu(e)-equivalent (7)Be solar neutrino flux of (3.10 +/- 0.15) x 10(9) cm(-2) s(-1) and, under the assumption of nu(e) transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51 +/- 0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0 sigma. A global solar neutrino analysis with free fluxes determines Phi(pp) = 6.06(-0.66)(+0.02) x 10(10) cm(-2) s(-1) and Phi(CNO) < 1.3 x 10(9) cm(-2) s(-1) (95% C.L.). These results significantly improve the precision with which the Mikheyev-Smirnov-Wolfenstein large mixing angle neutrino oscillation model is experimentally tested at low energy.
|
MiniBooNE Collaboration(Aguilar-Arevalo, A. A. et al), & Sorel, M. (2011). Measurement of the neutrino component of an antineutrino beam observed by a nonmagnetized detector. Phys. Rev. D, 84(7), 072005–14pp.
Abstract: Two methods are employed to measure the neutrino flux of the antineutrino-mode beam observed by the MiniBooNE detector. The first method compares data to simulated event rates in a high-purity nu(mu)-induced charged-current single pi(+) (CC1 pi(+)) sample while the second exploits the difference between the angular distributions of muons created in nu(mu) and nu(mu) charged-current quasielastic (CCQE) interactions. The results from both analyses indicate the prediction of the neutrino flux component of the predominately antineutrino beam is overestimated-the CC1 pi(+) analysis indicates the predicted nu(mu) flux should be scaled by 0: 76 +/- 0: 11, while the CCQE angular fit yields 0: 65 +/- 0: 23. The energy spectrum of the flux prediction is checked by repeating the analyses in bins of reconstructed neutrino energy, and the results show that the spectral shape is well-modeled. These analyses are a demonstration of techniques for measuring the neutrino contamination of antineutrino beams observed by future nonmagnetized detectors.
|
