Springer Theses

Search for Charginos Nearly Mass-Degenerate with the Lightest Neutralino

Based on a Disappearing-Track Signature in pp Collisions at √s = 8 TeV

Authors: Kazama, Shingo

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  • Nominated as an outstanding contribution by the University of Tokyo's Physics Department in 2014
  • Describes the search for long-lived massive particles based on a disappearing-track signature
  • Covers a new tracking algorithm to enhance a track reconstruction efficiency for charged winos having short decay length
  • Explores supersymmetric models with the pure neutral wino being the LSP, which are motivated by the property measurements of the Higgs boson at the LHC
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eBook $84.99
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  • ISBN 978-4-431-55657-2
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Hardcover $139.99
price for USA in USD
  • ISBN 978-4-431-55656-5
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  • Covid-19 shipping restrictions & severe weather in the US may cause delays
  • Usually ready to be dispatched within 3 to 5 business days, if in stock
Softcover $109.99
price for USA in USD
  • ISBN 978-4-431-56284-9
  • Free shipping for individuals worldwide
  • Institutional customers should get in touch with their account manager
  • Covid-19 shipping restrictions & severe weather in the US may cause delays
  • Usually ready to be dispatched within 3 to 5 business days, if in stock
About this book

In this book, the anomaly mediated supersymmetry breaking (AMSB) model is explored by searching for charged winos with their subsequent decays collected with the ATLAS detector at the Large Hadron Collider (LHC).

The author develops a new method, called “re-tracking,” to detect charged winos that decay before reaching the Semiconductor Tracker (SCT) detector. Because the nominal tracking algorithm at the ATLAS experiment requires at least seven successive hits in the inner tracking system, the sensitivity to charged winos having a fraction of a nanosecond in the past analysis was therefore limited. However, re-tracking requires a minimum of three pixel hits and provides a fully efficient tracking capability for charged winos traversing the pixel detector, resulting in around about 100 times greater efficiency for charged winos with a lifetime ~0.2 ns longer than that in past searches.

Signal topology is characterized by a jet with large transverse momentum (pT), large missing transverse energy, and a high-pT disappearing track. There are three types of back

ground tracks: interacting hadron tracks, charged leptons, and tracks with mismeasured pT. A background estimation based on the Monte Carlo (MC) simulation suffers from large uncertainties due to poor statistics and has difficulty simulating the properties of background tracks. Therefore, a data-driven approach has been developed by the author of the book to estimate the background track-pT spectrum.

No significant excess above the background expectation is observed for candidate tracks with large transverse momentum, and constraints on the AMSB model are obtained. The author shows that in the AMSB model, a charged wino mass below 270 GeV is excluded at 95 % confidence level, which also directly constrains the mass of wino dark matter.

Table of contents (13 chapters)

Table of contents (13 chapters)

Buy this book

eBook $84.99
price for USA in USD
  • ISBN 978-4-431-55657-2
  • Digitally watermarked, DRM-free
  • Included format: EPUB, PDF
  • ebooks can be used on all reading devices
  • Immediate eBook download after purchase
Hardcover $139.99
price for USA in USD
  • ISBN 978-4-431-55656-5
  • Free shipping for individuals worldwide
  • Institutional customers should get in touch with their account manager
  • Covid-19 shipping restrictions & severe weather in the US may cause delays
  • Usually ready to be dispatched within 3 to 5 business days, if in stock
Softcover $109.99
price for USA in USD
  • ISBN 978-4-431-56284-9
  • Free shipping for individuals worldwide
  • Institutional customers should get in touch with their account manager
  • Covid-19 shipping restrictions & severe weather in the US may cause delays
  • Usually ready to be dispatched within 3 to 5 business days, if in stock
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Bibliographic Information

Bibliographic Information
Book Title
Search for Charginos Nearly Mass-Degenerate with the Lightest Neutralino
Book Subtitle
Based on a Disappearing-Track Signature in pp Collisions at √s = 8 TeV
Authors
Series Title
Springer Theses
Copyright
2016
Publisher
Springer Japan
Copyright Holder
Springer Japan
eBook ISBN
978-4-431-55657-2
DOI
10.1007/978-4-431-55657-2
Hardcover ISBN
978-4-431-55656-5
Softcover ISBN
978-4-431-56284-9
Series ISSN
2190-5053
Edition Number
1
Number of Pages
XIII, 148
Topics