768 research outputs found
Exploiting the WH/ZH symmetry in the search for New Physics
We suggest to isolate the loop-induced gluon-initiated component ()
for associated production by using the similarity of the Drell-Yan-like
component for production to the process. We argue that the
cross-section ratio of the latter two processes can be predicted with high
theoretical accuracy. Comparing it to the experimental cross-section
ratio should allow to probe for New Physics in the component at the
HL-LHC. We consider typical BSM scenarios in order to exemplify the effect they
would have on the proposed observable.Comment: 22 pages, 10 figures. v2: Minor changes; matches published versio
Measurement of the t(t)over-bar production cross section in the dilepton channel in pp collisions at √s=8 TeV
The top-antitop quark (t (t) over bar) production cross section is measured in proton-proton collisions at root s = 8 TeV with the CMS experiment at the LHC, using a data sample corresponding to an integrated luminosity of 5.3 fb(-1). The measurement is performed by analysing events with a pair of electrons or muons, or one electron and one muon, and at least two jets, one of which is identified as originating from hadronisation of a bottom quark. The measured cross section is 239 +/- 2 (stat.) +/- 11 (syst.) +/- 6 (lum.) pb, for an assumed top-quark mass of 172.5 GeV, in agreement with the prediction of the standard model
Higgs Strahlung at the Large Hadron Collider in the 2-Higgs-Doublet Model
We present a calculation of all relevant contributions to associated
production of a Higgs boson with a weak gauge boson in the 2-Higgs-Doublet
Model (2HDM) at the LHC, , with and
. While for the mode, this mostly amounts to a simple
rescaling of the Standard Model (SM) cross section, the cross section
depends on several 2HDM parameters. The ratio ,
for which we present the currently most complete SM prediction, therefore
appears to be a sensitive probe of possible New Physics effects. We study its
numerical dependence on the top and bottom Yukawa couplings, including their
sign. Furthermore, we consider the ratio in exemplary 2HDM
scenarios and briefly address the effects in the boosted regime. Analogous
studies for other 2HDM scenarios will become possible with an upcoming version
of the program vh@nnlo which incorporates the 2HDM effects.Comment: 32 pages, 18 figures; v2: discussion of boosted regime added, typos
corrected, references added, version published in JHE
Higgs and Z boson associated production via gluon fusion in the SM and the 2HDM
We analyse the associated production of Higgs and boson via heavy-quark
loops at the LHC in the Standard Model and beyond. We first review the main
features of the Born production, and in particular discuss the
high-energy behaviour, angular distributions and boson polarisation. We
then consider the effects of extra QCD radiation as described by the
loop matrix elements, and find that they dominate at high Higgs transverse
momentum. We show how merged samples of 0-- and 1--jet multiplicities, matched
to a parton shower can provide a reliable description of differential
distributions in production. In addition to the Standard Model study,
results in a generic two-Higgs-doublet-model are obtained and presented for a
set of representative and experimentally viable benchmarks for ,
and production. We observe that various interesting features appear
either due to the resonant enhancement of the cross-section or to interference
patterns between resonant and non-resonant contributions.Comment: 29 pages, 12 figure
Associated production of Higgs boson with vector boson at threshold NLO in QCD
We present the results for the associated production of Higgs boson with
vector boson computed at threshold NLO in QCD. We use the recently
available result on the threshold contributions to the inclusive Drell-Yan
production cross-section at third order in strong coupling constant. We have
implemented it in the publicly available computer package vh@nnlo, thereby
obtaining the numerical impact of threshold NLO contributions for the first
time. We find that the inclusion of such corrections do reduce theoretical
uncertainties resulting from the renormalization scale.Comment: 14 pages, 3 figure
Prospects for Higgs physics at energies up to 100 TeV
We summarise the prospects for Higgs boson physics at future proton-proton
colliders with centre of mass (c.m.) energies up to 100 TeV. We first provide
the production cross sections for the Higgs boson of the Standard Model from 13
TeV to 100 TeV, in the main production mechanisms and in subleading but
important ones such as double Higgs production, triple production and
associated production with two gauge bosons or with a single top quark. We then
discuss the production of Higgs particles in beyond the Standard Model
scenarios, starting with the one in the continuum of a pair of scalar,
fermionic and vector dark matter particles in Higgs-portal models in various
channels with virtual Higgs exchange. The cross sections for the production of
the heavier CP-even and CP-odd neutral Higgs states and the charged Higgs
states in two-Higgs doublet models, with a specific study of the case of the
Minimal Supersymmetric Standard Model, are then given. The sensitivity of a 100
TeV proton machine to probe the new Higgs states is discussed and compared to
that of the LHC with a c.m. energy of 14 TeV and at high luminosity.Comment: 61 pages, 16 figures, 6 tables; review article. v2: numbers and
figures updated, aknowledgments modified, references added and typos
corrected. Matches the published versio
vh@nnlo-v2: new physics in Higgs Strahlung
Introducing version 2 of the code vh@nnlo [1], we study the effects of a number of new-physics scenarios on the Higgs-Strahlung process. In particular, the cross section is evaluated within a general 2HDM and the MSSM. While the Drell-Yan-like contributions are consistently taken into account by a simple rescaling of the SM result, the gluon-initiated contribution is supplemented by squark-loop mediated amplitudes, and by the s-channel exchange of additional scalars which may lead to conspicuous interference effects. The latter holds as well for bottom-quark initiated Higgs Strahlung, which is also included in the new version of vh@nnlo. Using an orthogonal rotation of the three Higgs CP eigenstates in the 2HDM and the MSSM, vh@nnlo incorporates a simple means of CP mixing in these models. Moreover, the effect of vector-like quarks in the SM on the gluon-initiated contribution can be studied. Beyond concrete models, vh@nnlo allows to include the effect of higher-dimensional operators on the production of CP-even Higgs bosons. Transverse momentum distributions of the final state Higgs boson and invariant mass distributions of the VÏ• final state for the gluon- and bottom-quark initiated contributions can be studied. Distributions for the Drell-Yan-like component of Higgs Strahlung can be included through a link to MCFM. vh@nnlo can also be linked to FeynHiggs and 2HDMC for the calculation of Higgs masses and mixing angles. It can also read these parameters from an SLHA-file as produced by standard spectrum generators. Throughout the manuscript, we highlight new-physics effects in various numerical examples, both at the inclusive level and for distributions
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