44 research outputs found
NNLO contributions to inclusive-jet production in DIS and determination of \alpha_s
We present the first calculation of inclusive jet production in
deep-inelastic scattering with approximate next-to-next-to-leading order
(aNNLO) contributions, obtained from a unified threshold resummation formalism.
The leading coefficients are computed analytically. We show that the aNNLO
contributions reduce the theoretical prediction for jet production in
deep-inelastic scattering, improve the description of the final HERA data in
particular at high photon virtuality Q^2 and increase the central fit value of
the strong coupling constant.Comment: 5 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1310.172
A 96 GeV Higgs boson in the N2HDM
We discuss a ∼3σ signal (local) in the light Higgs-boson search in the diphoton decay mode at ∼96GeV as reported by CMS, together with a ∼2σ excess (local) in the bb¯ final state at LEP in the same mass range. We interpret this possible signal as a Higgs boson in the 2 Higgs Doublet Model with an additional real Higgs singlet (N2HDM). We find that the lightest Higgs boson of the N2HDM can perfectly fit both excesses simultaneously, while the second lightest state is in full agreement with the Higgs-boson measurements at 125GeV, and the full Higgs-boson sector is in agreement with all Higgs exclusion bounds from LEP, the Tevatron and the LHC as well as other theoretical and experimental constraints. We show that only the N2HDM type II and IV can fit both the LEP excess and the CMS excess with a large ggF production component at ∼96GeV. We derive bounds on the N2HDM Higgs sector from a fit to both excesses and describe how this signal can be further analyzed at the LHC and at future e+e- colliders, such as the ILCThe work was supported in part by the MEINCOP (Spain) under contract FPA2016-78022-P and in part by the AEI through the grant IFT Centro de Excelencia Severo Ochoa SEV-2016-0597. The work of T.B. and S.H. was supported in part by the Spanish Agencia Estatal de Investigación (AEI), in part by the EU Fondo Europeo de Desarrollo Regional (FEDER) through the project FPA2016-78645-P, in part by the “Spanish Red Consolider MultiDark” FPA2017-90566-REDC. The work of T.B. was funded by Fundación La Caixa under ‘La Caixa-Severo Ochoa’ international predoctoral gran
Precise prediction for the Higgs-Boson Masses in the SSM
The SSM is a simple supersymmetric extension of the Standard Model
(SM) capable of predicting neutrino physics in agreement with experiment. In
this paper we perform the complete one-loop renormalization of the neutral
scalar sector of the SSM with one generation of right-handed neutrinos
in a mixed on-shell/ scheme. The renormalization
procedure is discussed in detail, emphasizing conceptual differences to the
minimal (MSSM) and next-to-minimal (NMSSM) supersymmetric standard model
regarding the field renormalization and the treatment of non-flavor-diagonal
soft mass parameters, which have their origin in the breaking of -parity in
the SSM. We calculate the full one-loop corrections to the neutral
scalar masses of the SSM. The one-loop contributions are supplemented
by available MSSM higher-order corrections. We obtain numerical results for a
SM-like Higgs boson mass consistent with experimental bounds. We compare our
results to predictions in the NMSSM to obtain a measure for the significance of
genuine SSM-like contributions. We only find minor corrections due to
the smallness of the neutrino Yukawa couplings, indicating that the Higgs boson
mass calculations in the SSM are at the same level of accuracy as in
the NMSSM. Finally we show that the SSM can accomodate a Higgs boson
that could explain an excess of events at as reported by CMS, as well as the excess of events observed at LEP at a similar mass scale.Comment: Version published in EPJC. Numerical analysis improved, numerical
results for NMSSM comparison changed accordingly, overall conclusions
unchanged. 56 pages, 12 figure
The 95.4 GeV di-photon excess at ATLAS and CMS
The ATLAS collaboration has recently reported the results of a low-mass
Higgs-boson search in the di-photon final state based on the full Run 2 data
set. The results are based on an improved analysis w.r.t. the previous
analysis, which included a part of the Run 2 data, with a substantially better
sensitivity. The ``model-dependent'' search carried out by ATLAS shows an
excess of events at a mass of about 95.4 GeV with a local significance of
. The results are compatible with a previously reported excess at
the same mass, but somewhat higher significance of , from the CMS
collaboration, also based on the full Run 2 data set. Combining the two results
(neglecting possible correlations) we find a signal strength of
, corresponding to
an excess of . In this work, we investigate the implications of
this result, updating a previous analysis based solely on the CMS Run 2 data.
We demonstrate that the ATLAS/CMS combined di-photon excess can be interpreted
as the lightest Higgs boson in a Two-Higgs doublet model that is extended by a
complex singlet (S2HDM) of Yukawa types II and IV, while being in agreement
with all other experimental and theoretical constraints.Comment: v.1: 9 pages, 2 figures. arXiv admin note: substantial text overlap
with arXiv:2303.1201
The "96 GeV excess" at the LHC
The CMS collaboration reported an intriguing \sim 3 sigma (local) excess at
96 GeV in the light Higgs-boson search in the diphoton decay mode. This mass
coincides with a \sim 2 sigma (local) excess in the bb final state at LEP. We
briefly review the proposed combined interpretations for the two excesses. In
more detail we review the interpretation of this possible signal as the
lightest Higgs boson in the 2 Higgs Doublet Model with an additional real Higgs
singlet (N2HDM). We show which channels have the best prospects for the
discovery of additional Higgs bosons at the upcoming Run 3 of the LHC.Comment: 7 pages, 1 figure. Talk presented at the IAS Program on High Energy
Physics (HEP) 2020. These proceedings complement with new material the
original paper, arXiv:1903.11661, and the subsequent arXiv:1910.06858,
arXiv:2002.06904. On popular demand we have included again a list of models
explaining the excesse
The Universal One-Loop Effective Action
We present the universal one-loop effective action for all operators of
dimension up to six obtained by integrating out massive, non-degenerate
multiplets. Our general expression may be applied to loops of heavy fermions or
bosons, and has been checked against partial results available in the
literature. The broad applicability of this approach simplifies one-loop
matching from an ultraviolet model to a lower-energy effective field theory
(EFT), a procedure which is now reduced to the evaluation of a combination of
matrices in our universal expression, without any loop integrals to evaluate.
We illustrate the relationship of our results to the Standard Model (SM) EFT,
using as an example the supersymmetric stop and sbottom squark Lagrangian and
extracting from our universal expression the Wilson coefficients of
dimension-six operators composed of SM fields.Comment: 30 pages, v2 contains additional comments and corrects typos, version
accepted for publication in JHE
Dimension-6 operator analysis of the CLIC sensitivity to new physics
We estimate the possible accuracies of measurements at the proposed CLICe+ e− collider of Higgs and W+W− production at centre-of-mass energies up to 3 TeV,
incorporating also Higgsstrahlung projections at higher energies that had not been considered previously, and use them to explore the prospective CLIC sensitivities to decoupled new physics. We present the resulting constraints on the Wilson coefficients of dimension6 operators in a model-independent approach based on the Standard Model effective field theory (SM EFT). The higher centre-of-mass energy of CLIC, compared to other projects such as the ILC and CEPC, gives it greater sensitivity to the coefficients of some of the operators we study. We find that CLIC Higgs measurements may be sensitive to new physics scales Λ = O(10) TeV for individual operators, reduced to O(1) TeV sensitivity for a global fit marginalising over the coefficients of all contributing operators. We give some examples
of the corresponding prospective constraints on specific scenarios for physics beyond the SM, including stop quarks and the dilaton/radion
Higgs-mass predictions in the MSSM and beyond
Predictions for the Higgs masses are a distinctive feature of supersymmetric
extensions of the Standard Model, where they play a crucial role in
constraining the parameter space. The discovery of a Higgs boson and the
remarkably precise measurement of its mass at the LHC have spurred new efforts
aimed at improving the accuracy of the theoretical predictions for the Higgs
masses in supersymmetric models. The "Precision SUSY Higgs Mass Calculation
Initiative" (KUTS) was launched in 2014 to provide a forum for discussions
between the different groups involved in these efforts. This report aims to
present a comprehensive overview of the current status of Higgs-mass
calculations in supersymmetric models, to document the many advances that were
achieved in recent years and were discussed during the KUTS meetings, and to
outline the prospects for future improvements in these calculations