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DTSTAMP:20261021T085436Z
LAST-MODIFIED:20170522T140637Z
DTSTART:20170612T140000Z
DTEND:20170612T150000Z
UID:event1772@bu.edu
URL:http://physics.bu.edu/internal/events/show/1772
SUMMARY:A Search for Heavy Fermionic Top Quark Partners with Charge 5/3 Dec
	aying to a Pair of Same-Sign Leptons wit the CMS Experiment
DESCRIPTION:Featuring Clint Richardson\n\nPart of the PhD Final Oral Exams.
	\n\nExamining Committee:   Tulika Bose\, Kevin Black\, Kenneth Lane\, Shyam
	 Erramilli\, James Rohlf\n\nAbstract:\n\nIn the millennia of recorded human
	 knowledge\, no model for describing the workings of Nature is as elegant o
	r complete as the Standard Model of Particle Physics (SM). However\, the SM
	 has several open questions and there exist multiple phenomena that it cann
	ot explain. A pressing question is related to the mass of the Higgs boson\,
	 whose value the SM has no natural way of explaining\, relying instead on t
	he fine tuning of parameters to one part in 10^(28). Many extensions of the
	 SM propose new interactions and particles which solve this problem. A part
	icularly common theme is that of new partners of the top quark\, which in s
	ome models are fermionic and have vectorial couplings to the SM charged wea
	k current. Such particles are referred to as vector-like quarks and represe
	nt a promising avenue of research.\n\nA search is presented for a vector-li
	ke quark with an exotic 5/3 charge (in units of the charge of an electron)\
	, referred to as an X5/3 particle. These particles are predicted in Composi
	te Higgs theories\, which rely on the masses of the X5/3 to be not more tha
	n ~ 2 TeV in order to solve the unnaturalness inherent in the mass of the H
	iggs boson. The search uses data collected by the CMS experiment in both 20
	15 and 2016 consisting of proton-proton collisions at a center-of-mass ener
	gy of 13 TeV at the CERN LHC. No significant excess of events is seen above
	 the predicted background and limits are placed on the mass of the new top 
	quark partner at 95% confidence level\, excluding masses less than 1200 (11
	60) GeV for X5/3 particles that decay with right-handed (left-handed) coupl
	ings to W bosons. These are the most stringent limits to date on the mass o
	f the X5/3 particle in this final state.\n\n![Clint](/resources/event-image
	/1772/b2db70b_small)
LOCATION:PRB 261\, 3 Cummington Mall\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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