Search For A New Bottomonium State Decaying To Upsilon 1s Pi Pi In Pp Collisions At Sqrt S
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Search For A New Bottomonium State Decaying To Upsilon 1s Pi Pi In Pp Collisions At Sqrt S
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Author :
language : en
Publisher:
Release Date : 2013
Search For A New Bottomonium State Decaying To Upsilon 1s Pi Pi In Pp Collisions At Sqrt S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
The results of a search for the bottomonium counterpart, denoted as $X_b$, of the exotic charmonium state X(3872) is presented. The analysis is based on a sample of pp collisions at $\sqrt{s}$ = 8 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 20.7 inverse femtobarns. The search looks for the exclusive decay channel $X_b \to \Upsilon(1S) \pi^+ \pi^-$ followed by $\Upsilon(1S) \to \mu^+ \mu^-$. No evidence for an $X_b$ signal is observed. Upper limits are set at the 95% confidence level on the ratio of the inclusive production cross sections times the branching fractions to $\Upsilon(1S) \pi^+ \pi^-$ of the $X_b$ and the $\Upsilon$(2S). The upper limits on the ratio are in the range 0.9-5.4% for $X_b$ masses between 10 and 11 GeV. These are the first upper limits on the production of a possible $X_b$ at a hadron collider.
Government Reports Announcements Index
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Author :
language : en
Publisher:
Release Date : 1987
Government Reports Announcements Index written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1987 with Science categories.
Observation Of The Upsilon 13dj Bottomonium State Through Decays To Pi Pi Upsilon 1s
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Author :
language : en
Publisher:
Release Date : 2010
Observation Of The Upsilon 13dj Bottomonium State Through Decays To Pi Pi Upsilon 1s written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
Suppression Of Upsilon 1s Upsilon 2s And Upsilon 3s Production In Pbpb Collisions At Sqrt S Nn
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Author :
language : en
Publisher:
Release Date : 2016
Suppression Of Upsilon 1s Upsilon 2s And Upsilon 3s Production In Pbpb Collisions At Sqrt S Nn written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
The production yields of Upsilon(1S), Upsilon(2S), and Upsilon(3S) quarkonium states are measured through their decays into muon pairs in the CMS detector, in PbPb and pp collisions at the centre-of-mass energy per nucleon pair of 2.76 TeV. The data correspond to integrated luminosities of 166 inverse microbarns and 5.4 inverse picobarns for PbPb and pp collisions, respectively. Differential production cross sections are reported as functions of Upsilon rapidity $y$ up to 2.4, and transverse momentum pt up to 20 GeV/c. A strong centrality-dependent suppression is observed in PbPb relative to pp collisions, by factors of up to ~2 and 8, for the Upsilon(1S) and Upsilon(2S) states, respectively. No significant dependence of this suppression is observed as a function of y or pt. The Upsilon(3S) state is not observed in PbPb collisions, which corresponds to a suppression for the centrality-integrated data by at least a factor of ~7 at a 95% confidence level. The observed suppression is in agreement with theoretical scenarios modeling the sequential melting of quarkonium states in a quark gluon plasma.
Strong Suppression Of Upsilon Excited States In Pb Pb Collisions At Square Root S Subscript Nn
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Author : Chad Steven Flores
language : en
Publisher:
Release Date : 2017
Strong Suppression Of Upsilon Excited States In Pb Pb Collisions At Square Root S Subscript Nn written by Chad Steven Flores and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
The relative yields of [upsilon] mesons produced in p + p and Pb+Pb collisions at [square root] s[subscript NN] = 5.02 TeV and reconstructed via the dimuon decay channel are measured using data collected by the CMS experiment. Double ratios are formed by comparing the yields of the excited states, [upsilon](2S) and [upsilon](3S), to the ground state, [upsilon](1S), in both Pb+Pb and p + p collisions at the same energy. The double ratios, [[upsilon](nS)/[upsilon](1S)][subscript PbPb] /[[upsilon](nS)/[upsilon](1S)][subscript pp] ,are measured to be 0.308 ± 0.055 (stat) ± 0.019 (syst) for the [upsilon](2S) and less than 0.26 at 95% confidence level for the [upsilon](3S). The double ratios are studied as a function of collision centrality, as well as dimuon transverse momentum, and rapidity. As a function ofcollision centrality the [upsilon](2S) double ratio is consistent with unity in the most peripheral (70–100%) bin and is consistent with zero in the most central (0–5%) bin. The [upsilon](2S) double ratio is consistent with a constant dependence on the kinematic variables, with a large suppression seen throughout the studied kinematic range. No significant [upsilon](3S) signal is found in the Pb+Pb data. The [upsilon](3S) double ratio is consistently below unity for all bins, including the most peripheral (50–100%) bin, indicating a strong suppression of the [upsilon](3S) relative to the [upsilon](1S).
Indications Of Suppression Of Excited Upsilon States In Pbpb Collisions At Sqrt S Nn
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Author :
language : en
Publisher:
Release Date : 2011
Indications Of Suppression Of Excited Upsilon States In Pbpb Collisions At Sqrt S Nn written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
A comparison of the relative yields of Upsilon resonances in the mu(+) mu( - ) decay channel in PbPb and pp collisions at a centre-of-mass energy per nucleon pair of 2.76 TeV, is performed with data collected with the CMS detector at the LHC. Using muons of transverse momentum above 4 GeV/c and pseudorapidity below 2.4, the double ratio of the Upsilon(2S) and Upsilon(3S) excited states to the Upsilon(1S) ground state in PbPb and pp collisions, (Upsilon(2S+3S)/Upsilon(1S)[PbPb])/(Upsilon(2S+3S)/Upsilon(1S)[pp]), is found to be 0.31 - 0.15 + 0.19 (stat.) +/- 0.03 (syst.). The probability to obtain the measured value, or lower, if the true double ratio is unity, has been calculated to be less than 1%.
Observation Of The Bottomonium Ground State In The Decay Y 3s To Ynb
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Author :
language : en
Publisher:
Release Date : 2008
Observation Of The Bottomonium Ground State In The Decay Y 3s To Ynb written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with categories.
The authors report the results of a search for the bottomonium ground state [eta]{sub b}(1S) in the photon energy spectrum with a sample of (109 ± 1) million of [Upsilon](3S) recorded at the [Upsilon](3S) recorded at the [Upsilon](3S) energy with the BABAR detector at the PEP-II B factory at SLAC. They observe a peak in the photon energy spectrum at E{sub [gamma]} = 921.2{sub -2.8}{sup +2.1}(stat) ± 2.4(syst) MeV with a significance of 10 standard deviations. They interpret the observed peak as being due to monochromatic photons from the radiative transition [Upsilon](3S) → {gamma} [eta]{sub b}(1S). This photon energy corresponds to an [eta]{sub b}(1S) mass of 9388.9{sub -2.3}{sup +3.1}(stat) ± 2.7(syst) MeV/c2. The hyperfine [Upsilon](1S)-[eta]{sub b}(1S) mass splitting is 71.4{sub -3.1}{sup +2.3}(stat) ± 2.7(syst) MeV/c2. The branching fraction for this radiative [Upsilon](3S) decay is estimated to be (4.8 ± 0.5(stat) ± 1.2(syst)) x 10−4.
Search For The Xb And Other Hidden Beauty States In The Pi Pi Upsilon 1s Channel At Atlas
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Author :
language : en
Publisher:
Release Date : 2014
Search For The Xb And Other Hidden Beauty States In The Pi Pi Upsilon 1s Channel At Atlas written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
This Letter presents a search for a hidden-beauty counterpart of the X(3872) in the mass ranges of 10.05-10.31 GeV and 10.40-11.00 GeV, in the channel Xb → [pi]+[pi]-[Upsilon] (1S)(→ [mu]+[mu]-), using 16.2 fb-1 of √s = 8 TeV pp collision data collected by the ATLAS detector at the LHC. No evidence for new narrow states is found, and upper limits are set on the product of the Xb cross section and branching fraction, relative to those of the [Upsilon](2S), at the 95% confidence level using the CLS approach. These limits range from 0.8% to 4.0%, depending on mass. For masses above 10.1 GeV, the expected upper limits from this analysis are the most restrictive to date. Searches for production of the [Upsilon] (13DJ), [Upsilon](10860), and [Upsilon](11020) states also reveal no significant signals.
Measurement Of The Dipion Mass Spectrum In The Decay X 3872 Right Arrow J Psi Pi Pi At The Cdfii Experiment
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Author : Alexander Yurevich Rakitin
language : en
Publisher:
Release Date : 2005
Measurement Of The Dipion Mass Spectrum In The Decay X 3872 Right Arrow J Psi Pi Pi At The Cdfii Experiment written by Alexander Yurevich Rakitin and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with categories.
We present a measurement of the dipion mass spectrum in the decay X(3872) [right arrow] J/ [psi] [pi]+ [pi]− using a 360 pb-1 sample of pp collisions at av [square root]s = 1.96 TeV collected with the CDF II detector at the Fermnilab Tevatron Collider. As a benchmark, we also extract the dipion mass distribution for [psi] (2s) [right arrow] J/ [psi] [pi]+ [pi]− decay. The X(3872) dipion mass spectrum is compared to QCD multipole expansion predictions for various charmonium states, as well as to the hypothesis [right arrow] J/ [psi] po. We find that the measured spectrum is compatible with 3S1 charmonium decaying to J/ [psi] [pi]+ [pi]− - and with the X(3872) - J/po hypothesis. There is, however, no 3S1 charmonium state available for assignment to the X(3872). The multipole expansion calculations for 1P1 and 3DJ states are in clear disagreement with the X(3872) data. For the [psi] (2S) the data agrees well with previously published results and to multipole expansion calculations for 3S1 charmonium. Other, non-charmonium, models for the X(3872) are described too. We conclude that since the dipion mass spectrum for X(3872) is compatible with J/pO hypothesis, the X(3872) should be C-positive. This conclusion is supported by recent results from Belle Collaboration which observed X(3872) -+ J/7y decay. We argue that if X(3872) is a charmonium, then it should be either ... state, decaying into J/ [psi] [pi]+ [pi]− in violation of isospin conservation. A non-charmonium assignment, such as DD* molecule, is also quite possible.
Search For B S And B To Dimuon Decays In Pp Collisions At 7 Tev
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Author :
language : en
Publisher:
Release Date : 2011
Search For B S And B To Dimuon Decays In Pp Collisions At 7 Tev written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
A search for the rare decays B(s) to dimuons and B0 to dimuons is performed in pp collisions at sqrt(s)=7 TeV, with a data sample corresponding to an integrated luminosity of 1.14 inverse femtobarns, collected by the CMS experiment at the LHC. In both cases, the number of events observed after all selection requirements is consistent with expectations from background and standard-model signal predictions. The resulting upper limits on the branching fractions are B(B(s) to mu+̂ mu-̂)