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5 Direct Searches for New Physics
electrons and large-R jets in the electron channel. The most important input variables
are the dilepton invariant mass, the scalar sum of the lepton p T and the jet masses
of the two leading- p T large-R jets. Three regions in the BDT output are used to
define the signal region. Because the BDT is adjusted to include the signal mass as
input [1281], the measured distributions change for each signal mass probed. The
analysis reports a lower limit on the mass of scalar LQs of 1480 GeV for B(LQ →
te) = 1 and and 1470 GeV for B(LQ → tμ) = 1. The LQ → te result comprises
the first experimental result from a direct search in this channel. Comparing the
expected limits with the previous analysis by CMS [1212], the sensitivity in the
LQ → tμ channel improved by 120 GeV. The obtained mass limits are weaker by
about 300 GeV than the ones obtained in an ATLAS search for LQs decaying to
electrons and muons together with first- and second-generation quarks using the same
dataset [1282]. This is a general difficulty of LQ searches involving top quarks, where
the different t decay modes and the difficulties in reconstructing and identifying the t
decay reduce the sensitivity compared to light-quark initiated high- p T jets. However,
this can also be encouraging because it shows the potential left for future analyses
in search for LQs decaying to top quarks.
5 Direct Searches for New Physics
electrons and large-R jets in the electron channel. The most important input variables
are the dilepton invariant mass, the scalar sum of the lepton p T and the jet masses
of the two leading- p T large-R jets. Three regions in the BDT output are used to
define the signal region. Because the BDT is adjusted to include the signal mass as
input [1281], the measured distributions change for each signal mass probed. The
analysis reports a lower limit on the mass of scalar LQs of 1480 GeV for B(LQ →
te) = 1 and and 1470 GeV for B(LQ → tμ) = 1. The LQ → te result comprises
the first experimental result from a direct search in this channel. Comparing the
expected limits with the previous analysis by CMS [1212], the sensitivity in the
LQ → tμ channel improved by 120 GeV. The obtained mass limits are weaker by
about 300 GeV than the ones obtained in an ATLAS search for LQs decaying to
electrons and muons together with first- and second-generation quarks using the same
dataset [1282]. This is a general difficulty of LQ searches involving top quarks, where
the different t decay modes and the difficulties in reconstructing and identifying the t
decay reduce the sensitivity compared to light-quark initiated high- p T jets. However,
this can also be encouraging because it shows the potential left for future analyses
in search for LQs decaying to top quarks.