Evidence for Exclusive $\gamma\gamma \to W^+ W^-$ Production and Constraints on Anomalous Quartic Gauge Couplings at $\sqrt{s}
Evidence for Exclusive $\gamma\gamma \to W^+ W^-$ Production and Constraints on Anomalous Quartic Gauge Couplings at $\sqrt{s}

Author:

Publisher:

Published: 2016

Total Pages:

ISBN-13:

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A search for exclusive or quasi-exclusive gamma-gamma to W+W- production, via pp to p(*) W+W- p(*) to p(*) mu+/- e-/+ at sqrt(s)=8 TeV, is reported using data corresponding to an integrated luminosity of 19.7 inverse femtobarns. Events are selected by requiring the presence of an electron-muon pair with large transverse momentum pt(mu+/- e-/+>) 30 GeV, and no associated charged particles detected from the same vertex. The 8 TeV results are combined with the previous 7 TeV results (obtained for 5.05 inverse femtobarns of data). In the signal region, 13 (2) events are observed over an expected background of 3.9 +/- 0.6 (0.84 +/-0.15) events for 8 (7) TeV, resulting in a combined excess of 3.4 sigma over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the standard model prediction for exclusive and quasi-exclusive gamma-gamma to W+W- production. Upper limits on the anomalous quartic gauge coupling operators a[W;0,C] (dimension-6) and f[M0,1,2,3] (dimension-8), the most stringent to date, are derived from the measured dilepton transverse momentum spectrum.

XXII DAE High Energy Physics Symposium
XXII DAE High Energy Physics Symposium

Author: Md. Naimuddin

Publisher: Springer

Published: 2018-05-23

Total Pages: 879

ISBN-13: 3319731718

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These proceedings gather invited and contributed talks presented at the XXII DAE-BRNS High Energy Physics (HEP) Symposium, which was held at the University of Delhi, India, on 12–16 December 2016. The contributions cover a variety of topics in particle physics, astroparticle physics, cosmology and related areas from both experimental and theoretical perspectives, namely (1) Neutrino Physics, (2) Standard Model Physics (including Electroweak, Flavour Physics), (3) Beyond Standard Model Physics, (4) Heavy Ion Physics & QCD (Quantum Chromodynamics), (5) Particle Astrophysics & Cosmology, (6) Future Experiments and Detector Development, (7) Formal Theory, and (8) Societal Applications: Medical Physics, Imaging, etc. The DAE-BRNS High Energy Physics Symposium, widely considered to be one of the leading symposiums in the field of Elementary Particle Physics, is held every other year in India and supported by the Board of Research in Nuclear Sciences (BRNS), Department of Atomic Energy (DAE), India. As many as 400 physicists and researchers attended the 22nd Symposium to discuss the latest advances in the field. A poster session was also organized to highlight the work and findings of young researchers. Bringing together the essential content, the book offers a valuable resource for both beginning and advanced researchers in the field.

Search for Anomalous Trilinear Couplings of Electroweak Gauge Bosons Using Angular Variables at 8́(s
Search for Anomalous Trilinear Couplings of Electroweak Gauge Bosons Using Angular Variables at 8́(s

Author: Kevin Siehl

Publisher:

Published: 2020

Total Pages: 87

ISBN-13:

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A study of techniques for improving limits placed on anomalous trilinear couplings of electroweak gauge bosons is presented. Electroweak gauge bosons couple to one another as well as to fermions. Deviations of these couplings from their standard model values would be a sign of new physics. Parameters that affect the couplings of the gauge bosons to each other also affect their helicity, which in turn may be measured from their decay products. Angles between the decay planes of the gauge bosons, as well as between their decay products, are measured. The analysis uses 35.9 fb 8́21 of proton-proton collision data from the LHC taken with the CMS detector. Building on a prior analysis that measured the fiducial cross section of pp 6́2 W W/W Z 6́2 lÎưjj, we show that angular variables can improve limits on anomalous couplings even further.