17,876 research outputs found
Exploring Extended Scalar Sectors with Di-Higgs Signals: A Higgs EFT Perspective
We consider extended scalar sectors of the Standard Model as
ultraviolet-complete motivations for studying the effective Higgs
self-interaction operators of the Standard Model effective field theory. We
investigate all motivated heavy scalar models which generate the dimension-6
effective operator, , at tree level and proceed to identify the full set
of tree-level dimension-six operators by integrating out the heavy scalars. Of
seven models which generate at tree level only two, quadruplets of
hypercharge and , generate only this operator. Next we perform
global fits to constrain relevant Wilson coefficients from the LHC single Higgs
measurements as well as the electroweak oblique parameters and . We find
that the parameter puts very strong constraints on the Wilson coefficient
of the operator in the triplet and quadruplet models, while the singlet
and doublet models could still have Higgs self-couplings which deviate
significantly from the standard model prediction. To determine the extent to
which the operator could be constrained, we study the dihiggs
signatures at the future 100 TeV collider and explore future sensitivity of
this operator. Projected onto the Higgs potential parameters of the extended
scalar sectors, with ab luminosity data we will be able to explore
the Higgs potential parameters in all seven models.Comment: 25 pages, 11 figures, 6 tables; version 3: match the JHEP published
versio
Ds+ -- Ds- Asymmetry in Photoproduction
Considering of the possible difference in strange and antistrange quark
distributions inside nucleon, we investigate the Ds+ -- Ds- asymmetry in
photoproduction in the framework of heavy-quark recombination mechanism. We
adopt two distribution models of strange sea, those are the light-cone
meson-baryon fluctuation model and the effective chiral quark model. Our
results show that the asymmetry induced by the strange quark distributions is
distinct, which is measurable in experiments. And, there are evident
differences between the predictions of our calculation and previous estimation.
Therefore, the experimental measurements on the Ds+ -- Ds- asymmetry may impose
a unique restriction on the strange-antistrange distribution asymmetry models.Comment: 11 page, 5 figure
Quantum Decoherence with Holography
Quantum decoherence is the loss of a system's purity due to its interaction
with the surrounding environment. Via the AdS/CFT correspondence, we study how
a system decoheres when its environment is a strongly-coupled theory. In the
Feynman-Vernon formalism, we compute the influence functional holographically
by relating it to the generating function of Schwinger-Keldysh propagators and
thereby obtain the dynamics of the system's density matrix.
We present two exactly solvable examples: (1) a straight string in a BTZ
black hole and (2) a scalar probe in AdS. We prepare an initial state that
mimics Schr\"odinger's cat and identify different stages of its decoherence
process using the time-scaling behaviors of R\'enyi entropy. We also relate
decoherence to local quantum quenches, and by comparing the time evolution
behaviors of the Wigner function and R\'enyi entropy we demonstrate that the
relaxation of local quantum excitations leads to the collapse of its
wave-function.Comment: 55 pages, 13 figures; v2 47 pages & 13 figs, minor revision to match
published versio
Search for anomalous top quark production at the early LHC
We present a detailed study of the anomalous top quark production with
subsequent decay at the LHC induced by model-independent flavor-changing
neutral-current couplings, incorporating the complete next-to-leading order QCD
effects. Our results show that, taking into account the current limits from the
Tevatron, the LHC with TeV may discover the anomalous coupling at
5 level for a very low integrated luminosity of 61 pb. The
discovery potentials for the anomalous couplings at the LHC are examined in
detail. We also discuss the possibility of using the charge ratio to
distinguish the and couplings.Comment: 4 pages, 3 figures, version appears in Phys. Rev. Let
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