3 research outputs found
The heavy quark search at the LHC
We explore further the discovery potential for heavy quarks at the LHC, with
emphasis on the and of a sequential fourth family associated with
electroweak symmetry breaking. We consider QCD multijets, ,
and single backgrounds using event generation based on
improved matrix elements and low sensitivity to the modeling of initial state
radiation. We exploit a jet mass technique for the identification of
hadronically decaying 's and 's, to be used in the reconstruction of the
or mass. This along with other aspects of event selection can reduce
backgrounds to very manageable levels. It even allows a search for both
and in the absence of -tagging, of interest for the early running of
the LHC. A heavy quark mass of order 600 GeV is motivated by the connection to
electroweak symmetry breaking, but our analysis is relevant for any new heavy
quarks with weak decay modes.Comment: 12 pages, 7 figure
Accurate QCD predictions for heavy-quark jets at the Tevatron and LHC
Heavy-quark jets are important in many of today's collider studies and
searches, yet predictions for them are subject to much larger uncertainties
than for light jets. This is because of strong enhancements in higher orders
from large logarithms, ln(p_t/m_Q). We propose a new definition of heavy-quark
jets, which is free of final-state logarithms to all orders and such that all
initial-state collinear logarithms can be resummed into the heavy-quark parton
distributions. Heavy-jet spectra can then be calculated in the massless
approximation, which is simpler than a massive calculation and reduces the
theoretical uncertainties by a factor of three. This provides the first ever
accurate predictions for inclusive b- and c-jets, and the latter have
significant discriminatory power for the intrinsic charm content of the proton.
The techniques introduced here could be used to obtain heavy-flavour jet
results from existing massless next-to-leading order calculations for a wide
range of processes. We also discuss the experimental applicability of our
flavoured jet definition.Comment: 22 pages, 7 figure