Search for CP Violation in Top Quark-antiquark Production and Decay in Proton-proton Collisions at $\sqrt{s}$
Search for CP Violation in Top Quark-antiquark Production and Decay in Proton-proton Collisions at $\sqrt{s}$

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Published: 2016

Total Pages:

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The results of a first search for CP violation in the production and decay of top quark-antiquark (ttbar) pairs are presented. The search is based on asymmetries in T-odd, triple-product correlation observables, where T is the time-reversal operator. The analysis uses a sample of proton-proton collisions at $\sqrt{s}$ TeV collected by the CMS experiment, corresponding to an integrated luminosity of 19.7 inverse femtobarns. Events are selected having one electron or muon and at least four jets. The T-odd observables are measured using four-momentum vectors associated with ttbar production and decay. The measured asymmetries exhibit no evidence for CP-violating effects, consistent with the expectation from the standard model.

CP Violation in Single Top Quark Production
CP Violation in Single Top Quark Production

Author: Weigang Geng

Publisher:

Published: 2012

Total Pages: 222

ISBN-13: 9781267528629

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We present a search for CP violation in single top quark production with the DØ experiment at the Tevatron proton-antiproton collider. CP violation in the top electroweak interaction results in different single top quark production cross sections for top and antitop quarks. We perform the search in the single top quark final state using 5.4 fb-1 of data, in the s-channel, t-channel, and for both combined. At this time, we do not see an observable CP asymmetry.

CP Violation in Single Top Quark Production
CP Violation in Single Top Quark Production

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Publisher:

Published: 2012

Total Pages: 239

ISBN-13:

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We present a search for CP violation in single top quark production with the DØ experiment at the Tevatron proton-antiproton collider. CP violation in the top electroweak interaction results in different single top quark production cross sections for top and antitop quarks. We perform the search in the single top quark final state using 5.4 fb-1 of data, in the s-channel, t-channel, and for both combined. At this time, we do not see an observable CP asymmetry.

Cp Violation
Cp Violation

Author: Cecilia Jarlskog

Publisher: World Scientific

Published: 1989-01-01

Total Pages: 733

ISBN-13: 9814632457

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Contents:CP Phenomenology:Introduction to CP Violation (C Jarlskog)CP-Violation in the K0-K0-System (K Kleinknecht)The Quark Mixing Matrix, Charm Decays and B Decays (S Stone)The Question of CP Noninvariance — As Seen through the Eyes of Neutral Beauty (I I Bigi et al.)In Search of CP Noninvariance in Heavy Quark Systems (L-L Chau)CP Violation at High Energy e+e- Colliders (J Bernabéu & M B Gavela)CP Violation in the Standard Model with Four Families (A Datta & E A Paschos)CP Effects When Neutrinos are their Own Antiparticles (B Kayser)On Spontaneous CP Violation Triggered by Scalar Bosons (I I Bigi & A I Sanda)CP Violation and Left-Right Symmetry (R N Mohapatra)CP Violation and Supersymmetry (R N Mohapatra)Electric Dipole Moments (S M Barr & W H Marciano)Special Topics: The Strong CP Problem (R D Peccei)CP Violation and Cosmology (P Langacker)Nonleptonic Interactions:The 1/N Approach to Nonleptonic Weak Interactions (A J Buras)Chiral Perturbation Theory Approach to Weak Amplitudes (E de Rafael)What We Learnt from Weak Decays of Heavy Quarks (B Stech)Weak Hamiltonian on the Lattice (G Martinelli) Readership: High energy physicists. Keywords:CP Violation;Quark Mixing Matrix;Charm Decays;B Decays;Nonleptic Interactions;Heavy QuarksReview: “Similar material is most often available in journals, but the book accomplishes a valuable service in drawing it together … the one that will probably have the greatest utility and longest lifespan is the survey of B meson physics by I Bigi, V Khoze, N Uraltsev and A Sanda … Bigi et al. here provide the most thorough and readable account of the issues that I know of. I have seen no review comparable to the excellent summary of electric dipole moments by S Barr and W Marciano … the volume offers a generally readable entry into this field for a reader who has a basic background in particle physics.” John F Donoghue Science “… this book performs a very useful service for anyone active or interested in CP violation, both as a source of primary information and as a work of reference.” K J Peach J Phys. G: Nucl. Part. Phys.

Search for R-parity Violating Decays of a Top Squark in Proton{u2013}proton Collisions at
Search for R-parity Violating Decays of a Top Squark in Proton{u2013}proton Collisions at

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Published: 2016

Total Pages: 24

ISBN-13:

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The results of a search for a supersymmetric partner of the top quark (top squark), pair-produced in proton-proton collisions at $\sqrt{s} =$ 8 TeV, are presented. The search, which focuses on R-parity violating, chargino-mediated decays of the top squark, is performed in final states with low missing transverse momentum, two oppositely charged electrons or muons, and at least five jets. The analysis uses a data sample corresponding to an integrated luminosity of 19.7 fb${̂-1}$ collected with the CMS detector at the LHC in 2012. The data are found to be in agreement with the standard model expectation, and upper limits are placed on the top squark pair production cross section at 95% confidence level. Assuming a 100% branching fraction for the top squark decay chain, $ \mathrm{ \tilde{t} \to t \tilde{\chi}{̂\pm}_1,\, \tilde{\chi}{̂\pm}_1 \to \ell\̂pm+jj } $, top squark masses less than 890 (1000) GeV for the electron (muon) channel are excluded for the first time in models with a single nonzero R-parity violating coupling $\lambda{̂\prime}_{ijk}$ $(i,j,k \leq 2)$, where $i,j,k$ correspond to the three generations.

Searches for CP Violation in Charmed Meson Decays
Searches for CP Violation in Charmed Meson Decays

Author: Hamish Gordon

Publisher: Springer

Published: 2014-06-07

Total Pages: 167

ISBN-13: 3319070673

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Our current understanding of the fundamental building blocks of the Universe, summarised by the Standard Model of particle physics, is incomplete. For example, it fails to explain why we do not see equal, or almost equal, numbers of particles and their antiparticle partners. To explain this asymmetry requires, among other effects, a mechanism known as charge-parity (CP) violation that causes differences between the rates at which particles and antiparticles decay. CP violation is seen in systems containing bottom and strange quarks, but not in those with up, charm or top quarks. This thesis describes searches for particle-antiparticle asymmetries in the decay rates of charmed mesons. No evidence of CP violation is found. With current sensitivities, an asymmetry large enough to observe probably could not be explained by the Standard Model. Instead an explanation could come from new physics, for example contributions from supersymmetric or other undiscovered heavy particles. In the thesis, the development of new techniques to search for these asymmetries is described. They are applied to data from the LHCb experiment at CERN to make precise measurements of asymmetries in the D^+->K^-K^+pi^+ decay channel. This is the most promising charged D decay for CP violation searches.

CP Violation
CP Violation

Author: Società italiana di fisica

Publisher: IOS Press

Published: 2006

Total Pages: 626

ISBN-13: 9781586036287

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Dealing with the CP violation, from quarks to leptons, this publication reviews the field, from both the theoretical and experimental point of view, while planning for the experimentation at LHC and considering possible facilities for kaon, B meson and neutrino physics.

CP Violating Anomalous Top-quark Coupling in P$\bar{p}$ Collision at $\sqrt{s}
CP Violating Anomalous Top-quark Coupling in P$\bar{p}$ Collision at $\sqrt{s}

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Publisher:

Published: 2011

Total Pages: 312

ISBN-13:

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We conduct the first study of the T-odd correlations in tt events produced in p{bar p} collision at the Fermilab Tevatron collider that can be used to search for CP violation. We select events which have lepton+jets final states to identify t{bar t} events and measure counting asymmetries of several physics observables. Based on the result, we search the top quark anomalous couplings at the production vertex at the Tevatron. In addition, Geant4 development, photon identification, the discrimination of a single photon and a photon doublet from [pi]° decay are discussed in this thesis.