1,341 research outputs found
LHCb: Wrong-Sign to Right-Sign Yield in Flavor Tagged Data at LHCb
No full textInitial results on wrong-sign decays based on the 2010 dataset are presented: the selection criteria, the yield, the time-integrated ratio of wrong-sign to right-sign () decays, and a decay time acceptance corrected ratio. The corrected ratio is measured to be . This analysis is the first step towards the measurement of the time-dependent wrong-sign/right-sign ratio from which mixing parameters may be extracted
Production cross sections of light and charmed mesons in e+e- annihilation near 10.58 GeV
No full textWe report measurements of production cross sections for +, 0, , *+, *0, , , 0, 0(980), +, 0, +, *+, *0, and *+ in +− collisions at a center-of-mass energy near 10.58 GeV. The data were recorded by the Belle experiment, consisting of 571 fb−1 at 10.58 GeV and 74 fb−1 at 10.52 GeV. Production cross sections are extracted as a function of the fractional hadron momentum . The measurements are compared to pythia Monte Carlo generator predictions with various fragmentation settings, including those that have increased fragmentation into vector mesons over pseudoscalar mesons. The cross sections measured for light hadrons are consistent with no additional increase of vector over pseudoscalar mesons. The charmed-meson cross sections are compared to earlier measurements—when available—including older Belle results, which they supersede. They are in agreement before application of an improved initial-state radiation correction procedure that causes slight changes in their shapes.Authors:
R. Seidl, I. Adachi, H. Aihara, T. Aushev, R. Ayad, Sw. Banerjee, K. Belous, J. Bennett, M. Bessner, B. Bhuyan, D. Biswas, D. Bodrov, M. Bračko, P. Branchini, T. E. Browder, A. Budano, M. Campajola, K. Chilikin, K. Cho, S.-K. Choi, Y. Choi, S. Choudhury, S. Das, G. De Nardo, G. De Pietro, F. Di Capua, J. Dingfelder, Z. Doležal, T. V. Dong, D. Dossett, P. Ecker, T. Ferber, B. G. Fulsom, V. Gaur, A. Giri, P. Goldenzweig, E. Graziani, Y. Guan, K. Gudkova, C. Hadjivasiliou, T. Hara, H. Hayashii, D. Herrmann, W.-S. Hou, C.-L. Hsu, K. Inami, N. Ipsita, A. Ishikawa, R. Itoh, M. Iwasaki, W. W. Jacobs, S. Jia, Y. Jin, K. K. Joo, A. B. Kaliyar, C. Kiesling, C. H. Kim, D. Y. Kim, K.-H. Kim, P. Kodyš, A. Korobov, S. Korpar, P. Križan, P. Krokovny, D. Kumar, K. Kumara, Y.-J. Kwon, T. Lam, L. K. Li, Y. B. Li, L. Li Gioi, J. Libby, D. Liventsev, Y. Ma, M. Masuda, T. Matsuda, D. Matvienko, M. Merola, K. Miyabayashi, R. Mussa, M. Nakao, A. Natochii, M. Niiyama, S. Nishida, S. Ogawa, H. Ono, G. Pakhlova, S. Pardi, J. Park, S.-H. Park, A. Passeri, S. Patra, S. Paul, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, T. Podobnik, E. Prencipe, M. T. Prim, G. Russo, S. Sandilya, L. Santelj, V. Savinov, G. Schnell, C. Schwanda, Y. Seino, K. Senyo, M. E. Sevior, W. Shan, J.-G. Shiu, B. Shwartz, J. B. Singh, E. Solovieva, M. Starič, M. Sumihama, M. Takizawa, K. Tanida, F. Tenchini, T. Uglov, Y. Unno, S. Uno, Y. Usov, C. Van Hulse, A. Vinokurova, A. Vossen, M.-Z. Wang, B. D. Yabsley, W. Yan, Y. Yook, C. Z. Yuan, L. Yuan, Z. P. Zhang, and V. Zhilich (Belle Collaboration
Search for high-mass dilepton resonances in pp collisions at root s=8 TeV with the ATLAS detector
No full textSee paper for full list of authors - 14 pages plus author list + cover page (31 pages total), 5 figures, 4 tables, submitted to Physical Review D, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2012-19/International audienceThis article describes a search for high-mass resonances decaying to a pair of photons using a sample of fb of collisions at TeV recorded with the ATLAS detector at the Large Hadron Collider. The data are found to be in agreement with the Standard Model prediction, and limits are reported in the framework of the Randall-Sundrum model. This theory leads to the prediction of graviton states, the lightest of which could be observed at the Large Hadron Collider. A lower limit of () TeV at 95% confidence level is set on the mass of the lightest graviton for couplings of ()
Dark matter interpretations of ATLAS searches for the electroweak production of supersymmetric particles in TeV proton-proton collisions
No full textSee paper for full list of authors - 25 pages plus author list + cover pages (43 pages total), 6 figures, 4 tables, submitted to JHEP, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2015-12/International audienceA selection of searches by the ATLAS experiment at the LHC for the electroweak production of SUSY particles are used to study their impact on the constraints on dark matter candidates. The searches use of proton-proton collision data at TeV. A likelihood-driven scan of a five-dimensional effective model focusing on the gaugino--higgsino and Higgs sector of the phenomenological minimal supersymmetric Standard Model is performed. This scan uses data from direct dark matter detection experiments, the relic dark matter density and precision flavour physics results. Further constraints from the ATLAS Higgs mass measurement and SUSY searches at LEP are also applied. A subset of models selected from this scan are used to assess the impact of the selected ATLAS searches in this five-dimensional parameter space. These ATLAS searches substantially impact those models for which the mass of the lightest neutralino is less than 65 GeV, excluding 86% of such models. The searches have limited impact on models with larger due to either heavy electroweakinos or compressed mass spectra where the mass splittings between the produced particles and the lightest supersymmetric particle is small
First measurement of the Λc+ → pη′ decay
No full textWe present the first measurement of the branching fraction of the singly Cabibbo-suppressed (SCS) decay → pη′ with η′ → ηπ+π−, using a data sample corresponding to an integrated luminosity of 981 fb−1, collected by the Belle detector at the KEKB e+e− asymmetric-energy collider. A significant → pη′ signal is observed for the first time with a signal significance of 5.4σ. The relative branching fraction with respect to the normalization mode → pK−π+ is measured to beBΛc+→pη′BΛc+→pK−π+=7.54±1.32±0.73×10−3,全ての著者は下記の通り。
The BELLE collaboration, S. X. Li, J. X. Cui, C. P. Shen, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, P. Behera, K. Belous, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, D. Bodrov, G. Bonvicini, J. Borah, A. Bozek, M. Bračko, P. Branchini, T. E. Browder, A. Budano, M. Campajola, D. Červenkov, M.-C. Chang, P. Chang, V. Chekelian, A. Chen, B. G. Cheon, K. Chilikin, H. E. Cho, K. Cho, S.-J. Cho, S.-K. Choi, Y. Choi, S. Choudhury, D. Cinabro, S. Cunliffe, S. Das, N. Dash, G. De Nardo, G. De Pietro, R. Dhamija, F. Di Capua, Z. Doležal, T. V. Dong, D. Epifanov, T. Ferber, D. Ferlewicz, B. G. Fulsom, R. Garg, V. Gaur, N. Gabyshev, A. Giri, P. Goldenzweig, B. Golob, E. Graziani, T. Gu, T. Hara, K. Hayasaka, H. Hayashii, W.-S. Hou, K. Inami, A. Ishikawa, M. Iwasaki, Y. Iwasaki, W. W. Jacobs, E.-J. Jang, S. Jia, Y. Jin, K. K. Joo, J. Kahn, A. B. Kaliyar, K. H. Kang, Y. Kato, T. Kawasaki, H. Kichimi, C. Kiesling, C. H. Kim, D. Y. Kim, Y.-K. Kim, K. Kinoshita, P. Kodyš, T. Konno, A. Korobov, S. Korpar, E. Kovalenko, P. Križan, R. Kroeger, P. Krokovny, M. Kumar, R. Kumar, K. Kumara, Y.-J. Kwon, T. Lam, M. Laurenza, S. C. Lee, J. Li, L. K. Li, Y. Li, L. Li Gioi, J. Libby, D. Liventsev, A. Martini, M. Masuda, T. Matsuda, D. Matvienko, S. K. Maurya, F. Meier, M. Merola, K. Miyabayashi, R. Mizuk, R. Mussa, M. Nakao, D. Narwal, Z. Natkaniec, A. Natochii, L. Nayak, N. K. Nisar, S. Nishida, K. Nishimura, K. Ogawa, S. Ogawa, H. Ono, P. Oskin, P. Pakhlov, G. Pakhlova, T. Pang, S. Pardi, S.-H. Park, S. Patra, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, T. Podobnik, V. Popov, M. T. Prim, M. Röhrken, A. Rostomyan, N. Rout, G. Russo, D. Sahoo, S. Sandilya, A. Sangal, T. Sanuki, V. Savinov, G. Schnell, J. Schueler, C. Schwanda, A. J. Schwartz, Y. Seino, K. Senyo, M. E. Sevior, M. Shapkin, C. Sharma, V. Shebalin, J.-G. Shiu, B. Shwartz, F. Simon, E. Solovieva, S. Stanič, M. Starič, Z. S. Stottler, M. Sumihama, K. Sumisawa, T. Sumiyoshi, W. Sutcliffe, M. Takizawa, U. Tamponi, K. Tanida, F. Tenchini, K. Trabelsi, M. Uchida, Y. Unno, K. Uno, S. Uno, P. Urquijo, S. E. Vahsen, R. Van Tonder, G. Varner, A. Vinokurova, E. Waheed, D. Wang, E. Wang, M.-Z. Wang, S. Watanuki, E. Won, X. Xu, B. D. Yabsley, W. Yan, H. Ye, J. H. Yin, Y. Yusa, Y. Zhai, V. Zhilich & V. Zhukovajournal articl
Search for hb (2P) →γχbJ (1P) at s =10.860 GeV
No full textIn the bottomonium sector, the hindered magnetic dipole transitions between P-wave states ℎ(2)→(1), =0, 1, 2, are expected to be severely suppressed according to the relativized quark model, due to the spin flip of the quark. Nevertheless, a recent model following the coupled-channel approach predicts the corresponding branching fractions to be enhanced by orders of magnitude. In this Letter, we report the first search for such transitions. We find no significant signals and set upper limits at 90% confidence level on the corresponding branching fractions: ℬ[ℎ(2)→0(1)]<2.7×10−1, ℬ[ℎ(2)→1(1)]<5.4×10−3 and ℬ[ℎ(2)→2(1)]<1.3×10−2. These values help to constrain the parameters of the coupled-channel models. The results are obtained using a 121.4 fb−1 data sample taken around √ =10.860 GeV with the Belle detector at the KEKB asymmetric-energy +− collider.Authors:
A. Boschetti, R. Mussa, U. Tamponi, I. Adachi, H. Aihara, D. M. Asner, T. Aushev, R. Ayad, Sw. Banerjee, K. Belous, J. Bennett, M. Bessner, D. Biswas, A. Bobrov, D. Bodrov, A. Bozek, M. Bračko, P. Branchini, T. E. Browder, A. Budano, M.-C. Chang, B. G. Cheon, K. Chilikin, K. Cho, S.-K. Choi, Y. Choi, S. Choudhury, G. De Nardo, G. De Pietro, R. Dhamija, F. Di Capua, Z. Doležal, T. V. Dong, P. Ecker, D. Epifanov, D. Ferlewicz, B. G. Fulsom, R. Garg, V. Gaur, A. Garmash, A. Giri, P. Goldenzweig, E. Graziani, T. Gu, Y. Guan, K. Gudkova, C. Hadjivasiliou, T. Hara, K. Hayasaka, H. Hayashii, S. Hazra, W.-S. Hou, C.-L. Hsu, K. Inami, N. Ipsita, R. Itoh, M. Iwasaki, W. W. Jacobs, Y. Jin, T. Kawasaki, C. Kiesling, C. H. Kim, D. Y. Kim, K.-H. Kim, Y.-K. Kim, K. Kinoshita, P. Kodyš, S. Korpar, E. Kovalenko, P. Križan, P. Krokovny, R. Kumar, K. Kumara, Y.-J. Kwon, T. Lam, D. Levit, L. K. Li, Y. B. Li, L. Li Gioi, D. Liventsev, Y. Ma, M. Masuda, T. Matsuda, D. Matvienko, F. Meier, M. Merola, K. Miyabayashi, R. Mizuk, G. B. Mohanty, M. Nakao, Z. Natkaniec, A. Natochii, L. Nayak, M. Nayak, S. Nishida, S. Ogawa, H. Ono, G. Pakhlova, J. Park, S.-H. Park, A. Passeri, S. Patra, S. Paul, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, T. Podobnik, E. Prencipe, M. T. Prim, N. Rout, G. Russo, S. Sandilya, L. Santelj, V. Savinov, G. Schnell, C. Schwanda, Y. Seino, K. Senyo, W. Shan, C. P. Shen, J.-G. Shiu, A. Sokolov, E. Solovieva, M. Starič, M. Sumihama, M. Takizawa, K. Tanida, F. Tenchini, R. Tiwary, M. Uchida, Y. Unno, S. Uno, A. Vinokurova, E. Wang, M.-Z. Wang, X. L. Wang, E. Won, B. D. Yabsley, J. Yelton, J. H. Yin, Y. Yook, and L. Yuan (Belle Collaboration
Search for single production of a vector-like quark via a heavy gluon in the 4b final state with the ATLAS detector in pp collisions at root s=8 TeV
No full textA search is performed for the process pp -> G* -> B-H(b) over bar/(B) over bar (H)b -> Hb (b) over bar -> b (b) over barb (b) over bar, predicted in composite Higgs scenarios, where G* is a heavy colour octet vector resonance and B-H a vector-like quark of charge -1/3. The data were obtained from pp collisions at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 19.5 fb(-1), recorded by the ATLAS detector at the LHC. The largest background, multijet production, is estimated using a data-driven method. No significant excess of events with respect to Standard Model predictions is observed, and upper limits on the production cross section times branching ratio are set. Comparisons to the predictions from a specific benchmark model are made, resulting in lower mass limits in the two-dimensional mass plane of m(G*) vs. m(BH). (c) 2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license
Search for new phenomena in events with a photon and missing transverse momentum in pp collisions at s√=13 TeV with the ATLAS detector
No full textSee paper for full list of authors - 23 pages (+ author list: 40 pages in total), 11 figures, 6 tables. Submitted to J. High Energy Phys., All figures including auxiliary figures are available at: this https URLInternational audienceResults of a search for new phenomena in events with an energetic photon and large missing transverse momentum with the ATLAS experiment at the Large Hadron Collider are reported. The data were collected in proton--proton collisions at a centre-of-mass energy of 13 TeV and correspond to an integrated luminosity of 3.2 fb−1. The observed data are in agreement with the Standard Model expectations. Exclusion limits are presented in models of new phenomena including pair production of dark matter candidates or large extra spatial dimensions. In a simplified model of dark matter and an axial-vector mediator, the search excludes mediator masses of up to 710 GeV for dark matter candidate masses up to 150 GeV. In an effective theory of dark matter production, values of the suppression scale M∗ up to 570 GeV are excluded and the effect of truncation for various coupling values is reported. For the ADD large extra spatial dimension model the search places more stringent limits than earlier searches in the same event topology, excluding MD up to about 2.3 (2.8) TeV for two (six) additional spatial dimensions; the limits are reduced by 20--40% depending on the number of additional spatial dimensions when applying a truncation procedure
Measurement of the masses and widths of the and baryons
No full textInternational audienceUsing 980 fb-1 of data collected with the Belle detector operating at the KEKB asymmetric-energy e+e- collider, we report the measurements of the masses, and the first measurements of the instrinsic widths, of the Σc(2455)+ and Σc(2520)+ charmed baryons. We find M(Σc(2455)+)-M(Λc+)=166.17±0.05-0.07+0.16 MeV/c2, Γ(Σc(2455)+)=2.3±0.3±0.3 MeV/c2, M(Σc(2520)+)-M(Λc+)=230.9±0.5-0.1+0.5 MeV/c2, and Γ(Σc(2520)+)=17.2-2.1-0.7+2.3+3.1 MeV/c2, where the uncertainties are statistical and systematic, respectively. These measurements can be used to test models of the underlying quark structure of the Σc states
A measurement of material in the ATLAS tracker using secondary hadronic interactions in 7 TeV pp collisions
No full textSee paper for full list of authors, 28 pages plus author list + cover pages (45 pages total),14 figures, 8 tables, submitted to Journal of Instrum., All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/PERF-2015-06/International audienceKnowledge of the material in the ATLAS inner tracking detector is crucial in understanding the reconstruction of charged-particle tracks, the performance of algorithms that identify jets containing b-hadrons and is also essential to reduce background in searches for exotic particles that can decay within the inner detector volume. Interactions of primary hadrons produced in pp collisions with the material in the inner detector are used to map the location and amount of this material. The hadronic interactions of primary particles may result in secondary vertices, which in this analysis are reconstructed by an inclusive vertex-finding algorithm. Data were collected using minimum-bias triggers by the ATLAS detector operating at the LHC during 2010 at centre-of-mass energy = 7 TeV, and correspond to an integrated luminosity of nb. Kinematic properties of these secondary vertices are used to study the validity of the modelling of hadronic interactions in simulation. Secondary-vertex yields are compared between data and simulation over a volume of about 0.7 m around the interaction point, and agreement is found within overall uncertainties
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