A search for the K−pp bound state in the 3He(K−in-flight, n) reaction at J-PARC

We have collected the first physics data of an experimental search for the simplest kaonic nuclear bound state, " K − pp", by the 3He( K − n) reaction at J-PARC. We confirmed that our spectrometer system works as designed and observed clear peak structure composed of the quasi-elastic K − " n " → K − n and the charge-exchange K − " p " → ¯ K 0 n reactions in the forward neutron spectrum

Searches for transverse momentum dependent flow vector fluctuations in Pb-Pb and p-Pb collisions at the LHC

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPThe measurement of azimuthal correlations of charged particles is presented for Pb-Pb collisions at root S-NN 2.76 TeV and p-Pb collisions at root S-NN 5.02 TeV with the ALICE detector at the CERN Large Hadron Collider. These correlations are measured for the second, third and fourth order flow vector in the pseudorapidity region vertical bar eta vertical bar 0.8 as a function of centrality and transverse momentum pT using two observables, to search for evidence of PT-dependent flow vector fluctuations. For Ph-Ph collisions at 2.76 TeV, the measurements indicate that PT-dependent fluctuations are only present for the second order flow vector. Similar results have been found for p-Pb collisions at 5.02 TeV. These measurements are compared to hydrodynamic model calculations with event-by-event geometry fluctuations in the initial state to constrain the initial conditions and transport properties of the matter created in Ph-Ph and p-Pb collisions.9133CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informaçãoSem informaçãoSem informaçãoThe ALICE collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE collaboration gratefully acknowledges the resources and support provided by all Grid centres and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences and Nationalstiftung fur Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Universidade Federal do Rio Grande do Sul (UFRGS), Financiadora de Estudos e Projetos (Finep) and Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Brazil; Ministry of Science & Technology of China (MSTC), National Natural Science Foundation of China (NSFC) and Ministry of Education of China (MOEC), China; Ministry of Science, Education and Sport and Croatian Science Foundation, Croatia; Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research Natural Sciences, the Carlsberg Foundation and Danish National Research Foundation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat a l'Energie Atomique (CEA) and Institut National de Physique Nucleaire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS), France; Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie (BMBF) and GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Germany; General Secretariat for Research and Technology, Ministry of Education, Research and Religions, Greece; National Research, Development and Innovation Office, Hungary; Department of Atomic Energy Government of India (DAE) and Council of Scientific and Industrial Research (CSIR), New Delhi, India; Indonesian Institute of Science, Indonesia; Centro Fermi Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi and Istituto Nazionale di Fisica Nucleare (INFN), Italy; Institute for Innovative Science and Technology, Nagasaki Institute of Applied Science (IIST), Japan Society for the Promotion of Science (JSPS) KAKENHI and Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnologia, through Fondo de Cooperacion Internacional en Ciencia y Tecnologia (FONCICYT) and Direccion General de Asuntos del Personal Academico (DGAPA), Mexico; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; The Research Council of Norway, Norway; Commission on Science and Technology for Sustainable Development in the South (COMSATS), Pakistan; Pontificia Universidad Catolica del Peril, Peru; Ministry of Science and Higher Education and National Science Centre, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Korea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics and Romanian National Agency for Science, Technology and Innovation, Romania; Joint Institute for Nuclear Research (JINR), Ministry of Education and Science of the Russian Federation and National Research Centre Kurchatov Institute, Russia; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foundation of South Africa, South Africa; Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Cubaenergia, Cuba, Ministerio de Ciencia e Innovacion and Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Spain; Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; National Science and Technology Development Agency (NSDTA), Suranaree University of Technology (SUT) and Office of the Higher Education Commission under NRU project of Thailand, Thailand; Turkish Atomic Energy Agency (TAEK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America

Searches for transverse momentum dependent flow vector fluctuations in Pb-Pb and p-Pb collisions at the LHC

The measurement of azimuthal correlations of charged particles is presented for Pb-Pb collisions at sNN=2.76 TeV and p-Pb collisions at sNN=5.02 TeV with the ALICE detector at the CERN Large Hadron Collider. These correlations are measured for the second, third and fourth order flow vector in the pseudorapidity region |η| < 0.8 as a function of centrality and transverse momentum pT using two observables, to search for evidence of pT-dependent flow vector fluctuations. For Pb-Pb collisions at 2.76 TeV, the measurements indicate that pT-dependent fluctuations are only present for the second order flow vector. Similar results have been found for p-Pb collisions at 5.02 TeV. These measurements are compared to hydrodynamic model calculations with event-by-event geometry fluctuations in the initial state to constrain the initial conditions and transport properties of the matter created in Pb–Pb and p–Pb collisions

AEgIS experiment: Status & outlook

The AEGIS experiment1 (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is planned to perform the first measurement of the gravitational acceleration on antimatter by observing the free fall of antihydrogen atoms. By combining techniques based on recent developments in the production of positronium and its laser excitation to Rydberg states, such a study seems indeed to be feasible for neutral antimatter. We present here some of the experimental techniques involved in the experiment as well as the status of the detector test envisioned for the gravity measurement

AEgIS experiment: Status & outlook

none63The AEGIS experiment1 (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) is planned to perform the first measurement of the gravitational acceleration on antimatter by observing the free fall of antihydrogen atoms. By combining techniques based on recent developments in the production of positronium and its laser excitation to Rydberg states, such a study seems indeed to be feasible for neutral antimatter. We present here some of the experimental techniques involved in the experiment as well as the status of the detector test envisioned for the gravity measurement.noneLansonneur P.; Aghion S.; Amsler C.; Bonomi G.; Brusa R.S.; Caccia M.; Caravita R.; Castelli F.; Cerchiari G.; Comparat D.; Consolati G.; Demetrio A.; Di Noto L.; Doser M.; Evans C.; Ferragut R.; Fesel J.; Fontana A.; Gerber S.; Giammarchi M.; Gligorova A.; Guatieri F.; Haider S.; Hinterberger A.; Holmestad H.; Kellerbauer A.; Khalidova O.; Krasnicky D.; Lagomarsino V.; Lebrun P.; Malbrunot C.; Mariazzi S.; Marton J.; Matveev V.; Mazzotta Z.; Muller S.R.; Nebbia G.; Nedelec P.; Oberthaler M.; Pacico N.; Pagano D.; Penasa L.; Petracek V.; Prelz F.; Prevedelli M.; Ravelli L.; Rienaecker B.; Robert J.; Rhone O.M.; Rotondi A.; Sacerdoti M.; Sandaker H.; Santoro R.; Simon M.; Smestad L.; Sorrentino F.; Testera G.; Tietje I.C.; Widmann E.; Yzombard P.; Zimmer C.; Zmeska J.; Zurlo N.Lansonneur, P.; Aghion, S.; Amsler, C.; Bonomi, G.; Brusa, R. S.; Caccia, M.; Caravita, R.; Castelli, F.; Cerchiari, G.; Comparat, D.; Consolati, G.; Demetrio, A.; Di Noto, L.; Doser, M.; Evans, C.; Ferragut, R.; Fesel, J.; Fontana, A.; Gerber, S.; Giammarchi, M.; Gligorova, A.; Guatieri, F.; Haider, S.; Hinterberger, A.; Holmestad, H.; Kellerbauer, A.; Khalidova, O.; Krasnicky, D.; Lagomarsino, V.; Lebrun, P.; Malbrunot, C.; Mariazzi, S.; Marton, J.; Matveev, V.; Mazzotta, Z.; Muller, S. R.; Nebbia, G.; Nedelec, P.; Oberthaler, M.; Pacico, N.; Pagano, D.; Penasa, L.; Petracek, V.; Prelz, F.; Prevedelli, M.; Ravelli, L.; Rienaecker, B.; Robert, J.; Rhone, O. M.; Rotondi, A.; Sacerdoti, M.; Sandaker, H.; Santoro, R.; Simon, M.; Smestad, L.; Sorrentino, F.; Testera, G.; Tietje, I. C.; Widmann, E.; Yzombard, P.; Zimmer, C.; Zmeska, J.; Zurlo, N

A search for the K−pp bound state in the 3He(K−in-flight, n) reaction at J-PARC

We have collected the first physics data of an experimental search for the simplest kaonic nuclear bound state, “K− pp”, by the 3He(K− n) reaction at J-PARC. We confirmed that our spectrometer system works as designed and observed clear peak structure composed of the quasi-elastic K−“n” → K−n and the charge-exchange K−“p” → ¯̅K0n reactions in the forward neutron spectrum

Dielectron and heavy-quark production in inelastic and high-multiplicity proton-proton collisions at root s=13 TeV

The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p T ) at midrapidity (|y e |<0.8) in proton–proton (pp) collisions at a centre-of-mass energy of s=13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at s=7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: dσ cc¯ /dy| y=0 =974±138(stat.)±140(syst.)±214(BR)μb and dσ bb¯ /dy| y=0 =79±14(stat.)±11(syst.)±5(BR)μb using PYTHIA simulations and dσ cc¯ /dy| y=0 =1417±184(stat.)±204(syst.)±312(BR)μb and dσ bb¯ /dy| y=0 =48±14(stat.)±7(syst.)±3(BR)μb for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various p T intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of p T . Upper limits for the contribution of virtual direct photons are extracted at 90% confidence level and found to be in agreement with pQCD calculations

Dielectron and heavy-quark production in inelastic and high-multiplicity proton-proton collisions at root s=13 TeV

The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (pT) at midrapidity (|ye|<0.8) in proton\u2013proton (pp) collisions at a centre-of-mass energy 1as = 13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at 1as = 7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: d\u3c3cc \u304/dy|y=0 = 974 \ub1 138(stat.) \ub1 140(syst.) \ub1 214(BR) \u3bcb and d\u3c3bb \u304/dy|y=0 =79\ub114(stat.)\ub111(syst.)\ub15(BR) \u3bcb using PYTHIA simulations and d\u3c3cc \u304/dy|y=0 = 1417 \ub1 184(stat.) \ub1 204(syst.) \ub1 312(BR) \u3bcb and d\u3c3bb \u304/dy|y=0 = 48 \ub1 14(stat.) \ub1 7(syst.) \ub1 3(BR) \u3bcb for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various pT intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of pT. Upper limits for the contribution of virtual direct photons are extracted at 90% confidence level and found to be in agreement with pQCD calculations

Dielectron and heavy-quark production in inelastic and high-multiplicity proton–proton collisions at s=13TeV

The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p T ) at midrapidity (|y e |<0.8) in proton–proton (pp) collisions at a centre-of-mass energy of s=13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at s=7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: dσ cc¯ /dy| y=0 =974±138(stat.)±140(syst.)±214(BR)μb and dσ bb¯ /dy| y=0 =79±14(stat.)±11(syst.)±5(BR)μb using PYTHIA simulations and dσ cc¯ /dy| y=0 =1417±184(stat.)±204(syst.)±312(BR)μb and dσ bb¯ /dy| y=0 =48±14(stat.)±7(syst.)±3(BR)μb for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various p T intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of p T . Upper limits for the contribution of virtual direct photons are extracted at 90% confidence level and found to be in agreement with pQCD calculations

Medium modification of the shape of small-radius jets in central Pb-Pb collisions at root s(NN)=2:76 TeV

Abstract: We present the measurement of a new set of jet shape observables for track- based jets in central Pb-Pb collisions at √sNN = 2.76 TeV. The set of jet shapes includes the first radial moment or angularity, g; the momentum dispersion, pTD; and the differ- ence between the leading and sub-leading constituent track transverse momentum, LeSub. These observables provide complementary information on the jet fragmentation and can constrain different aspects of the theoretical description of jet-medium interactions. The jet shapes were measured for a small resolution parameter R = 0.2 and were fully corrected to particle level. The observed jet shape modifications indicate that in-medium fragmentation is harder and more collimated than vacuum fragmentation as obtained by PYTHIA cal- culations, which were validated with the measurements of the jet shapes in proton-proton collisions at √s = 7 TeV. The comparison of the measured distributions to templates for quark and gluon-initiated jets indicates that in-medium fragmentation resembles that of quark jets in vacuum. We further argue that the observed modifications are not consistent with a totally coherent energy loss picture where the jet loses energy as a single colour charge, suggesting that the medium resolves the jet structure at the angular scales probed by our measurements (R = 0.2). Furthermore, we observe that small-R jets can help to isolate purely energy loss effects from other effects that contribute to the modifications of the jet shower in medium such as the correlated background or medium response