Diffractively Produced Z Bosons in the Muon Decay Channel in P-pbar Collisions at S**(1/2) PDF Download
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Author: Tamsin L. Edwards
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Languages : en
Pages : 156
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The first analysis of diffractively produced Z bosons in the muon decay channel is presented, using data taken by the D0 detector at the Tevatron at {radical}s = 1.96 TeV. The data sample corresponds to an integrated luminosity of 109 pb{sup -1}. The diffractive sample is defined using the fractional momentum loss {zeta} of the intact proton or antiproton measured using the calorimeter and muon detector systems. In a sample of 10791 (Z/{gamma})* {yields} {mu}{sup +}{mu}{sup -} events, 24 diffractive candidate events are found with {zeta}
Author: Tamsin L. Edwards
Publisher:
ISBN:
Category :
Languages : en
Pages : 156
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Book Description
The first analysis of diffractively produced Z bosons in the muon decay channel is presented, using data taken by the D0 detector at the Tevatron at {radical}s = 1.96 TeV. The data sample corresponds to an integrated luminosity of 109 pb{sup -1}. The diffractive sample is defined using the fractional momentum loss {zeta} of the intact proton or antiproton measured using the calorimeter and muon detector systems. In a sample of 10791 (Z/{gamma})* {yields} {mu}{sup +}{mu}{sup -} events, 24 diffractive candidate events are found with {zeta}
![Diffractively Produced Z Bosons in the Muon Decay Channel in P[p]̄ Collisions as [s] PDF](https://books.google.com/books/content/images/frontcover/NZMacgAACAAJ?fife=w80-h100)
Author: Tamsin Louisa Edwards
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ISBN:
Category :
Languages : en
Pages : 156
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![Measurement of Z-boson Production in Pb+Pb and P+p Collisions Via the Electron and Muon Decay Channels at [squareroot]s(NN) PDF](https://books.google.com/books/content/images/frontcover/ZN7TsgEACAAJ?fife=w80-h100)
Author: Michael David Gardner
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ISBN: 9781321608588
Category :
Languages : en
Pages :
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Experiments over the last decade at the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory have yielded evidence for the formation of the new state of matter called the quark-gluon plasma (QGP). Normally, quarks (and their associated gluons) are found only in colorless doublets (mesons) or triplets (baryons), but when raised above the cross-over threshold at a temperature of ∼ 175 MeV, a strongly-coupled partonic medium of asymptotically free quarks and gluons is expected to form. The focus of heavy-ion physics at both the RHIC and Large Hadron Collider (LHC) experiments has been to study physical processes that allow for a better grasp of the properties of this medium. Because of the large center-of-mass energy per nucleon pair ([squareroot]s(NN)) of 2.76 TeV in Pb+Pb collisions at the LHC and substantial delivered integrated luminosities, the study of new processes in nucleus-nucleus collisions has become possible. One of those processes is Z-boson production, which due to it not interacting strongly, being produced in hard collisions and having a decay channel that does not interact with the QGP, can act as a control in understanding the cold nuclear matter effects present in heavy-ion collisions. This dissertation presents the measurement of the production of Z bosons in the dimuon and dielectron decay channels in Pb+Pb and p+p collisions at [squareroot]s(NN) of 2.76 TeV obtained by the CMS experiment at the LHC. The analysis is based on the data sample collected during the Pb+Pb run in 2011, which corresponds to an integrated luminosity of 150 [mu]b−1 and on the p+p data sample collected in 2013, at the same center-of-mass energy, with an integrated luminosity of 5.4 pb−1. The ratio of Pb+Pb to p+p yields, scaled by the number of incoherent nucleon-nucleon collisions, R(AA), is expected to be equal to unity if there are no nuclear effects modifying the production of the Z boson in the Pb+Pb collisions. The R(AA) for centrality-integrated Z-boson production is found to be 1.06 ± 0.05 (stat) ± 0.08 (syst) in the dimuon channel and 1.02 ± 0.08 (stat) ± 0.15 (syst) in the dielectron channel, and shows no nuclear modification across the rapidity, transverse momentum and centrality bins measured. This result demonstrates that the binary-collision scaling is seen to hold in the kinematic region studied, which is expected for a colorless probe that is unaffected by a deconfined QGP. It also opens avenues to study processes that are strongly modified by the QGP, by using Z production as a control.
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Category :
Languages : en
Pages : 22
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The production of Z bosons in pPb collisions at √sNN = 5.02TeV is studied by the CMS experiment via the electron and muon decay channels. The inclusive cross section is compared to pp collision predictions, and found to scale with the number of elementary nucleon-nucleon collisions. The differential cross sections as a function of the Z boson rapidity and transverse momentum are measured. Though they are found to be consistent within uncertainty with theoretical predictions both with and without nuclear effects, the forward-backward asymmetry suggests the presence of nuclear effects at large rapidities. These results provide new data for constraining nuclear parton distribution functions.
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Languages : en
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With this research, the ATLAS Collaboration measures the inclusive production of Z bosons via their decays into electron and muon pairs in p + Pb collisions at \(\sqrt{s_{\mathrm{NN}}} = 5.02\) TeV at the Large Hadron Collider. The measurements are made using data corresponding to integrated luminosities of 29.4 and 28.1 nb-1 for Z → ee and Z → [mu][mu], respectively. The results from the two channels are consistent and combined to obtain a cross section times the Z → ll branching ratio, integrated over the rapidity region
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Languages : en
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We report on a search for anomalous production of Z pairs through a massive resonance decay in data corresponding to 2.5-2.9 fb−1 of integrated luminosity in p{bar p} collisions at √s = 1.96 TeV using the CDF II detector at the Fermilab Tevatron. This analysis, with more data and channels where the Z bosons decay to muons or jets, supersedes the 1.1 fb−1 four-electron channel result previously published by CDF. In order to maintain high efficiency for muons, we use a new forward tracking algorithm and muon identification requirements optimized for these high signal-to-background channels. Predicting the dominant backgrounds in each channel entirely from sideband data samples, we observe four-body invariant mass spectra above 300 GeV/c2 that are consistent with background. We set limits using the acceptance for a massive graviton resonance that are 7-20 times stronger than the previously published direct limits on resonant ZZ production.
![Study of Z Production in PbPb and Pp Collisions at [arrow]](https://books.google.com/books/content/images/frontcover/uEV5AQAACAAJ?fife=w80-h100)
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Languages : en
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The production of Z bosons is studied in the dimuon and dielectron decay channels in PbPb and pp collisions at [arrow]"NN = 2.76 TeV, using data collected by the CMS experiment at the LHC. The PbPb data sample corresponds to an integrated luminosity of about 166 [mu]b-1, while the pp data sample collected in 2013 at the same nucleon-nucleon centre-of-mass energy has an integrated luminosity of 5.4 pb-1. The Z boson yield is measured as a function of rapidity, transverse momentum, and collision centrality. The ratio of PbPb to pp yields, scaled by the number of inelastic nucleon-nucleon collisions, is found to be 1.06 " 0.05 (stat) " 0.08 (syst) in the dimuon channel and 1.02 " 0.08 (stat) " 0.15 (syst) in the dielectron channel, for centrality-integrated Z boson production. This binary collision scaling is seen to hold in the entire kinematic region studied, as expected for a colourless probe that is unaffected by the hot and dense QCD medium produced in heavy ion collisions.
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Languages : en
Pages : 8
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The production rate and kinematics of photons produced in association with Z bosons are studied using 2 fb−1 of p{bar p} collision data collected at the Collider Detector at Fermilab. The cross section for p{bar p} → ll−? + X (where the leptons l are either muons or electrons with dilepton mass M{sub l{ell}}> 40 GeV/c2, and where the photon has transverse energy E{sub T}{sup?}> 7 GeV and is well separated from the leptons) is 4.6 ± 0.2 (stat) ± 0.3 (syst) ± 0.3 (lum) pb, which is consistent with standard model expectations. We use the photon ET distribution from Z{gamma} events where the Z has decayed to?+?−, e+e−, or?{bar {nu}} to set limits on anomalous (non-standard-model) trilinear couplings between photons and Z bosons.
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Languages : en
Pages : 162
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The search for the production of the Standard Model Z boson in association with a W boson is motivated and discussed. This is performed using 4.3 fb−1 of Tevatron Run II data collected with the CDF detector in (square root)s = 1.96 TeV proton anti-proton collisions. This is a signature-based analysis where the W boson decays semileptonically into a high-P{sub T} electron or muon plus a neutrino, and where the Z boson decays into two b quark jets (b-jets). We increase the signal-to-background ratio by identifying the b-quarks in the jets with a new neural network-based algorithm. Another neural network then uses kinematic information to distinguish WZ to further increase the signal-to-background ratio. Since our sensitivity is still not enough to achieve an observation, we set a 95% Confidence Level upper limit on the product of the WZ production cross section and its branching fraction to the decay products specified above, and express it as a ratio to the theoretical Standard Model prediction. The resulting limit is 3.9 x SM (3.9 x SM expected).
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Languages : en
Pages : 22
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A search for Z bosons in the mu+̂mu-̂ decay channel has been performed in PbPb collisions at a nucleon-nucleon centre of mass energy = 2.76 TeV with the CMS detector at the LHC, in a 7.2 inverse microbarn data sample. The number of opposite-sign muon pairs observed in the 60--120 GeV/c2̂ invariant mass range is 39, corresponding to a yield per unit of rapidity (y) and per minimum bias event of (33.8 +/- 5.5 (stat) +/- 4.4 (syst)) 10{̂-8}, in the.
