BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:From SCT luminosity to compressed SUSY  - Claire Malone (Universit
 y of Cambridge)
DTSTART:20220322T160000Z
DTEND:20220322T170000Z
UID:TALK169169@talks.cam.ac.uk
CONTACT:William Fawcett
DESCRIPTION:This talk covers both the improvements of luminosity measureme
 nts of pp collisions at ATLAS\, underpinning all measurements made by the 
 detector and a search for one of the most theoretically viable extensions 
 to the SM: supersymmetry.\n\nATLAS uses mainly event-counting algorithms t
 o measure luminosity\, which break down at higher luminosities. If the ATL
 AS SCT (part of the ATLAS inner detector) can be employed as a luminometer
  using hit-counting algorithms\, this issue may be mitigated. I will show 
 that the SCT can feasibly operate as a luminometer when recording two-or-m
 ore strip clusters with the standard binary readout mode. Thus\, the SCT c
 an measure the luminosity with an accuracy within 10% of two of ATLAS’s 
 existing luminometers: LUCID and TileCal.\n\nAn analysis of an experimenta
 lly challenging region of phase space\, where stop decays have a compresse
 d mass spectrum\, using the full Run-2 ATLAS dataset is presented. I show 
 how the aMT2 kinematic variable\, designed to give a lower limit on pair-p
 roduced particle masses\, is found to be effective at differentiating SUSY
  decays from the SM background when used as an upper bound. Secondary vert
 ex information and significance variables are also employed to design a se
 arch in this region of parameter space. Stop quarks are excluded up to 500
  GeV and mass splittings between the stop and the neutralino are found to 
 be excluded up to 130 GeV in the specific scenario considered\, compliment
 ing the exclusion limits found by other ATLAS searches for stop decays wit
 h one-lepton final states.
LOCATION:Ryle Seminar Room
END:VEVENT
END:VCALENDAR