We give an introduction to several regularization schemes that deal with ultraviolet and infrared singularities appearing in higher-order computations in quantum field theories. Comparing the ...computation of simple quantities in the various schemes, we point out similarities and differences between them.
In this manuscript, we report the outcome of the topical workshop:
paving the way to alternative NNLO strategies
(
https://indico.ific.uv.es/e/WorkStop-ThinkStart_3.0
), by presenting a discussion ...about different frameworks to perform precise higher-order computations for high-energy physics. These approaches implement novel strategies to deal with infrared and ultraviolet singularities in quantum field theories. A special emphasis is devoted to the local cancellation of these singularities, which can enhance the efficiency of computations and lead to discover novel mathematical properties in quantum field theories.
Higgs-mass predictions in the MSSM and beyond Slavich, P.; Heinemeyer, S.; Bagnaschi, E. ...
European physical journal. C, Particles and fields,
05/2021, Letnik:
81, Številka:
5
Journal Article
Recenzirano
Odprti dostop
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.
Physics at the e+e- linear collider Moortgat-Pick, G.; Baer, H.; Battaglia, M. ...
The European physical journal. C, Particles and fields,
08/2015, Letnik:
75, Številka:
8
Journal Article
Recenzirano
Odprti dostop
A comprehensive review of physics at an
e
+
e
-
linear collider in the energy range of
s
=
92
GeV–3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well ...as astroparticle physics. The report focusses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.
This paper presents the beam dynamics systematic corrections and their uncertainties for the Run-1 dataset of the Fermilab Muong−2Experiment. Two corrections to the measured muon precession ...frequencyωamare associated with well-known effects owing to the use of electrostatic quadrupole (ESQ) vertical focusing in the storage ring. An average vertically oriented motional magnetic field is felt by relativistic muons passing transversely through the radial electric field components created by the ESQ system. The correction depends on the stored momentum distribution and the tunes of the ring, which has relatively weak vertical focusing. Vertical betatron motions imply that the muons do not orbit the ring in a plane exactly orthogonal to the vertical magnetic field direction. A correction is necessary to account for an average pitch angle associated with their trajectories. A third small correction is necessary, because muons that escape the ring during the storage time are slightly biased in initial spin phase compared to the parent distribution. Finally, because two high-voltage resistors in the ESQ network had longer than designedRCtime constants, the vertical and horizontal centroids and envelopes of the stored muon beam drifted slightly, but coherently, during each storage ring fill. This led to the discovery of an important phase-acceptance relationship that requires a correction. The sum of the corrections toωamis0.50±0.09ppm; the uncertainty is small compared to the 0.43 ppm statistical precision ofωam.
The amplitude relevant for Higgs production via gluon fusion is computed in the four-dimensional helicity scheme (fdh) and in dimensional reduction (dred) at the two-loop level in the limit of heavy ...top quarks. The required renormalization is developed and described in detail, including the treatment of evanescent Formula omitted-scalar contributions. In fdh and dred there are additional dimension-5 operators generating the Hgg vertices, where g can either be a gluon or an -scalar. An appropriate operator basis is given and the operator mixing through renormalization is described. The results of the present paper provide building blocks for further computations, and they allow one to complete the study of the infrared divergence structure of two-loop amplitudes in fdh and dred.
We calculate supersymmetric two-loop corrections to the anomalous magnetic moment of the muon, consisting of diagrams with a closed scalar fermion or fermion loop and gauge and/or Higgs boson ...exchange. We discuss the numerical impact of each subclass of diagrams and determine the leading contributions. We analyze in detail constraints from experimental information on the Higgs boson mass, Δ
ρ, and the branching ratios of
B→
X
s
γ and
B
s
→
μ
+
μ
−. If these constraints are taken into account, the largest possible effect of our two-loop corrections is reduced from more than 3
σ (in terms of the current experimental error) to ∼0.5
σ, such that the influence on the total supersymmetric prediction is smaller than previously estimated. However, exceptions arise in rather extreme parameter scenarios with a strong non-universality between the soft breaking parameters in the stop and sbottom sectors.
A
bstract
We investigate the regularization-scheme dependence of scattering amplitudes in massless QCD and find that the four-dimensional helicity scheme (FDH) and dimensional reduction (DRED) are ...consistent at least up to NNLO in the perturbative expansion if renormalization is done appropriately. Scheme dependence is shown to be deeply linked to the structure of UV and IR singularities. We use jet and soft functions defined in soft-collinear effective theory (SCET) to efficiently extract the relevant anomalous dimensions in the different schemes. This result allows us to construct transition rules for scattering amplitudes between different schemes (CDR, HV, FDH, DRED) up to NNLO in massless QCD. We also show by explicit calculation that the hard, soft and jet functions in SCET are regularization-scheme independent.
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