3,302 research outputs found
Precision constraints on the top-quark effective field theory at future lepton colliders
We examine the constraints that future lepton colliders would impose on the
effective field theory describing modifications of top-quark interactions
beyond the standard model, through measurements of the process. Statistically optimal observables are exploited to constrain
simultaneously and efficiently all relevant operators. Their constraining power
is sufficient for quadratic effective-field-theory contributions to have
negligible impact on limits which are therefore basis independent. This is
contrasted with the measurements of cross sections and forward-backward
asymmetries. An overall measure of constraints strength, the global determinant
parameter, is used to determine which run parameters impose the strongest
restriction on the multidimensional effective-field-theory parameter space.Comment: 5 pages, contribution to DIS 2017 proceeding
The same-sign top signature of R-parity violation
Baryonic R-parity violation could explain why low-scale supersymmetry has not
yet been discovered at colliders: sparticles would be hidden in the intense
hadronic activity. However, if the known flavor structures are any guide, the
largest baryon number violating couplings are those involving the top/stop, so
a copious production of same-sign top-quark pairs is in principle possible.
Such a signal, with its low irreducible background and efficient identification
through same-sign dileptons, provides us with tell-tale signs of baryon number
violating supersymmetry. Interestingly, this statement is mostly independent of
the details of the supersymmetric mass spectrum. So, in this paper, after
analyzing the sparticle decay chains and lifetimes, we formulate a simplified
benchmark strategy that covers most supersymmetric scenarios. We then use this
information to interpret the same-sign dilepton searches of CMS, draw
approximate bounds on the gluino and squark masses, and extrapolate the reach
of the future 14 TeV runs.Comment: 32 pages, 12 figures, 3 tables, 1 appendi
Fundamentals of Philosophy - an introduction
A very basic introduction meant for Chinese lay people, who only have a background in the official historic-materialist worldview.
A version in Chinese is available as åŸºç¡€å“²å¦ â€• 概论, philpapers rec DUR-
The leptonic future of the Higgs
Precision study of electroweak symmetry breaking strongly motivates the
construction of a lepton collider with center-of-mass energy of at least 240
GeV. Besides Higgsstrahlung (), such a collider would measure
weak boson pair production () with an astonishing precision. The
weak-boson-fusion production process () provides an
increasingly powerful handle at higher center-of-mass energies. High energies
also benefit the associated top-Higgs production () that is
crucial to constrain directly the top Yukawa coupling. The impact and
complementarity of differential measurements, at different center-of-mass
energies and for several beam polarization configurations, are studied in a
global effective-field-theory framework. We define a "global determinant
parameter" (GDP) which characterizes the overall strengthening of constraints
independently of the choice of operator basis. The reach of the CEPC, CLIC,
FCC-ee, and ILC designs is assessed.Comment: 55 pages, lots of figures, v2: references added, minor corrections,
extended discussions on quadratic EFT contributions and beam polarization
effects, matches published version in JHE
NPEFix: Automatic Runtime Repair of Null Pointer Exceptions in Java
Null pointer exceptions, also known as null dereferences are the number one
exceptions in the field. In this paper, we propose 9 alternative execution
semantics when a null pointer exception is about to happen. We implement those
alternative execution strategies using code transformation in a tool called
NPEfix. We evaluate our prototype implementation on 11 field null dereference
bugs and 519 seeded failures and show that NPEfix is able to repair at runtime
10/11 and 318/519 failures
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