Measurement of the Single Top Quark Production Cross Section at the Square Root of S PDF Download
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Author: Mark Anthony Padilla
Publisher:
ISBN:
Category : Particle accelerators
Languages : en
Pages : 165
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Book Description
The s channel has a Gaussian significance of 1.6[sigma], the t channel 5.5[sigma], and the s + t 4.3[sigma]. The results are consistent with the standard model predictions within one standard deviation. By combining these results with the results for two other analyses (using different MVA techniques) improved results of: Combined s + t channels : [sigma](ppbar [arrow right] tb + X, tqb + X) = 3.43 + 0.73 - 0.74 pb, t channel : [sigma](ppbar [arrow right] tqb + X) = 2.90 + 0.59 - 0.59 pb. were obtained. These give a 5.6[sigma] significance for the combined s + t channel and 5.5[sigma] for the t channel.
Author: Mark Anthony Padilla
Publisher:
ISBN:
Category : Particle accelerators
Languages : en
Pages : 165
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Book Description
The s channel has a Gaussian significance of 1.6[sigma], the t channel 5.5[sigma], and the s + t 4.3[sigma]. The results are consistent with the standard model predictions within one standard deviation. By combining these results with the results for two other analyses (using different MVA techniques) improved results of: Combined s + t channels : [sigma](ppbar [arrow right] tb + X, tqb + X) = 3.43 + 0.73 - 0.74 pb, t channel : [sigma](ppbar [arrow right] tqb + X) = 2.90 + 0.59 - 0.59 pb. were obtained. These give a 5.6[sigma] significance for the combined s + t channel and 5.5[sigma] for the t channel.
Author:
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Category :
Languages : en
Pages : 189
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Book Description
Within the standard model top quarks are predicted to be most often produced in pairs via the strong interaction. However they can also be produced singly through the weak interation. This is a rarer process with many experimental challenges. It is interesting because it provides a new window to search for evidence of physics beyond the standard model picture, such as a fourth generation of quarks or to search for insight into the Higgs Mechanism. Single top production also provides a direct way to calculate the CKM matrix element Vtb. This thesis presents new measurements for single top quark production in the s+t, s and t channels using 5.4 fb-1 of data collected at the DØ detector at Fermilab in Batavia, IL. The analysis was performed using Boosted decision trees to separate signal from background and Bayesian statistcs to calculate all the cross sections.
Author: David James Goldstein
Publisher:
ISBN:
Category :
Languages : en
Pages : 284
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Book Description
![Measurement of the T-Channel Single Top Quark Production Cross Section in Pp Collisions at Sqrt[s] PDF](https://books.google.com/books/content/images/frontcover/dIxHzQEACAAJ?fife=w80-h100)
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Category :
Languages : en
Pages :
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Electroweak production of the top quark is measured in pp collisions at sqrt(s) = 7 TeV, using a dataset collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. With an event selection optimized for t-channel production, two complementary analyses are performed. The first one exploits the special angular properties of the signal, together with background estimates from data. The second approach uses a multivariate analysis technique to probe the compatibility with signal topology expected from electroweak top quark production. The combined measurement of the cross section is 83.6 +/- 29.8 (stat.+syst.) +/- 3.3 (lumi.) pb, consistent with the standard model expectation.
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Category :
Languages : en
Pages :
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The cross section for the production of single top quarks in the $t$ channel is measured in proton-proton collisions at 13 TeV with the CMS detector at the LHC. The analyzed data correspond to an integrated luminosity of 2.3 fb$^{-1}$. The event selection requires one muon and two jets where one of the jets is identified as originating from a bottom quark. Several kinematic variables are then combined into a multivariate discriminator to distinguish signal from background events. A fit to the distribution of the discriminating variable yields a total cross section of 232 $\pm$ 13 (stat) $\pm$ 28 (syst) pb and a ratio of top quark and top antiquark production of $R_{t\textrm{-ch.}}= $ 1.81 $\pm$ 0.18 (stat) $\pm$ 0.15 (syst). From the total cross section the absolute value of the CKM matrix element $V_{\mathrm{tb}}$ is calculated to be 1.03 $\pm$ 0.07 (exp) $\pm$ 0.02 (theo). All results are in agreement with the standard model predictions.
![Measurement of the Top Quark Pair Production Cross Section with 1.12 Fb−1 of Pp̄ Collisions at [square-root] S PDF](https://books.google.com/books/content/images/frontcover/Xu-ANwAACAAJ?fife=w80-h100)
Author: Daniel Joseph Sherman
Publisher:
ISBN:
Category : Cross sections (Nuclear physics)
Languages : en
Pages : 502
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Book Description
![Measurement of the Top Anti-top Quark Pair Production Cross-section in the [tau] + Jets Channel at [square Root of S] PDF](https://books.google.com/books/content/images/frontcover/eUEsrgEACAAJ?fife=w80-h100)
Author: Teeba Rashid
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ISBN:
Category : Hadron interactions
Languages : en
Pages : 195
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Author:
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Category :
Languages : en
Pages : 43
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Author:
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Category :
Languages : en
Pages : 31
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The top quark pair production cross section is measured in dilepton events with one electron or muon, and one hadronically decaying tau lepton from the decay t anti-t to (l nu(l)) (tau nu(tau)) b anti-b, where l can be either an electron or a muon. The data sample corresponds to an integrated luminosity of 2.0 inverse femtobarns for the electron channel and 2.2 inverse femtobarns for the muon channel, collected by the CMS detector at the LHC. This is the first measurement of the t anti-t cross section explicitly including tau leptons in proton-proton collisions at sqrt(s)=7 TeV. The measured value sigma(t anti-t) = 143 +/- 14 (stat.) +/- 22 (syst.) +/- 3 (lumi.) pb is consistent with the standard model predictions.
Author:
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Category :
Languages : en
Pages : 8
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The author reports on the observation of electroweak production of single top quarks in p{bar p} collisions at (square root)s = 1.96 Tev using 2.3 fb−1 of data collected with the D0 detector at the fermilab Tevatron Collider. Using events containing an isolated electron or muon, missing transverse energy, two, three or four jets, with one or two of them identified as originating from the fragmentation of a b quark, the measured cross section for the process p{bar p} --> tb + X, tqb + X is 3.94 ± 0.88 pb (for a top quark mass of 170 GeV). the probability to measure a cross section at this value or higher in the absence of signal is 2.5 x 10−7, corresponding to a 5.0 standard deviation significance. Using the same dataset, the measured cross sections for the t- and the s-channel processes when determined simultaneously with no assumption on their relative production rate are 3.14{sub -0.80}{sup +0.94} pb and 1.05 ± 0.81 pb respectively, consistent with standard model expectations. The measured t-channel cross section has a significance of 4.8 standard deviations, representing the first evidence for the production of an individual single top process to be detected.
