40 research outputs found
The NNLO gluon fusion Higgs production cross-section with many heavy quarks
We consider extensions of the Standard Model with a number of additional
heavy quarks which couple to the Higgs boson via top-like Yukawa interactions.
We construct an effective theory valid for a Higgs boson mass which is lighter
than twice the lightest heavy quark mass and compute the corresponding Wilson
coefficient through NNLO. We present numerical results for the gluon fusion
cross-section at the Tevatron for an extension of the Standard Model with a
fourth generation of heavy quarks. The gluon fusion cross-section is enhanced
by a factor of roughly 9 with respect to the Standard Model value. Tevatron
experimental data can place stringent exclusion limits for the Higgs mass in
this model.Comment: 14 pages, 1 tabl
Simultaneous decoupling of bottom and charm quarks
We compute the decoupling relations for the strong coupling, the light quark
masses, the gauge-fixing parameter, and the light fields in QCD with heavy
charm and bottom quarks to three-loop accuracy taking into account the exact
dependence on . The application of a low-energy theorem allows the
extraction of the three-loop effective Higgs-gluon coupling valid for
extensions of the Standard Model with additional heavy quarks from the
decoupling constant of .Comment: 30 page
Finite top quark mass effects in NNLO Higgs boson production at LHC
We present next-to-next-to-leading order corrections to the inclusive
production of the Higgs bosons at the CERN Large Hadron Collider (LHC)
including finite top quark mass effects. Expanding our analytic results for the
partonic cross section around the soft limit we find agreement with a very
recent publication by Harlander and Ozeren \cite{Harlander:2009mq}.Comment: 15 page
Three-loop \beta-functions for top-Yukawa and the Higgs self-interaction in the Standard Model
We analytically compute the dominant contributions to the \beta-functions for
the top-Yukawa coupling, the strong coupling and the Higgs self-coupling as
well as the anomalous dimensions of the scalar, gluon and quark fields in the
unbroken phase of the Standard Model at three-loop level. These are mainly the
QCD and top-Yukawa corrections. The contributions from the Higgs
self-interaction which are negligible for the running of the top-Yukawa and the
strong coupling but important for the running of the Higgs self-coupling are
also evaluated.Comment: 22 pages, 7 figures. Few extra citations are added; the plots are
improved. Results in computer readable form can be retrieved from
http://www-ttp.particle.uni-karlsruhe.de/Progdata/ttp12/ttp12-012
in the Two Higgs Doublet Model up to Next-to-Next-to-Leading Order in QCD
We compute three-loop matching corrections to the Wilson coefficients
and in the Two Higgs Doublet Model by applying expansions for small,
intermediate and large charged Higgs boson masses. The results are used to
evaluate the branching ratio of to next-to-next-to
leading order accuracy, and to determine an updated lower limit on the charged
Higgs boson mass. We find \mhplus \ge 380 GeV at 95% confidence level when
the recently completed BABAR data analysis is taken into account. Our results
for the charged Higgs contribution to the branching ratio exhibit considerably
weaker sensitivity to the matching scale , as compared to previous
calculations.Comment: 20 pages, 15 figures; v2: minor modifications, matches published
version in JHE
Light MSSM Higgs boson mass to three-loop accuracy
The light CP even Higgs boson mass, Mh, is calculated to three-loop accuracy
within the Minimal Supersymmetric Standard Model (MSSM). The result is
expressed in terms of DRbar parameters and implemented in the computer program
H3m. The calculation is based on the proper approximations and their
combination in various regions of the parameter space. The three-loop effects
to Mh are typically of the order of a few hundred MeV and opposite in sign to
the two-loop corrections. The remaining theory uncertainty due to higher order
perturbative corrections is estimated to be less than 1 GeV.Comment: 39 pages, 13 figures. v2: minor changes, typos fixe
Production of scalar and pseudo-scalar Higgs bosons to next-to-next-to-leading order at hadron colliders
We consider the production of intermediate-mass CP-even and CP-odd Higgs
bosons in proton-proton and proton-anti-proton collisions. We extend the
recently published results for the complete next-to-next-to-leading order
calculation for a scalar Higgs boson to the pseudo-scalar case and present
details of the calculation that might be useful for similar future
investigations. The result is based on an expansion in the limit of a heavy top
quark mass and a subsequent matching to the expression obtained in the limit of
infinite energy. For a Higgs boson mass of 120 GeV the deviation from the
infinite-top quark mass result is small. For 300 GeV, however, the
next-to-next-to-leading order corrections for a scalar Higgs boson exceed the
effective-theory result by about 9% which increases to 22% in the pseudo-scalar
case. Thus in this mass range the effect on the total cross section amounts to
about 2% and 6%, respectively, which may be relevant in future precision
studies.Comment: 29 page
The broad spectrum of unbearable suffering in end of life cancer studied in dutch primary care
<p>Abstract</p> <p>Background</p> <p>Unbearable suffering most frequently is reported in end-of-life cancer patients in primary care. However, research seldom addresses unbearable suffering. The aim of this study was to comprehensively investigate the various aspects of unbearable suffering in end-of-life cancer patients cared for in primary care.</p> <p>Methods</p> <p>Forty four general practitioners recruited end-of-life cancer patients with an estimated life expectancy of half a year or shorter. The inclusion period was three years, follow-up lasted one additional year. Practices were monitored bimonthly to identify new cases. Unbearable aspects in five domains and overall unbearable suffering were quantitatively assessed (5-point scale) through patient interviews every two months with a comprehensive instrument. Scores of 4 (serious) or 5 (hardly can be worse) were defined unbearable. The last interviews before death were analyzed. Sources providing strength to bear suffering were identified through additional open-ended questions.</p> <p>Results</p> <p>Seventy six out of 148 patients (51%) requested to participate consented; the attrition rate was 8%, while 8% were alive at the end of follow-up. Sixty four patients were followed up until death; in 60 patients interviews were complete. Overall unbearable suffering occurred in 28%. A mean of 18 unbearable aspects was present in patients with serious (score 4) overall unbearable suffering. Overall, half of the unbearable aspects involved the domain of traditional medical symptoms. The most frequent unbearable aspects were weakness, general discomfort, tiredness, pain, loss of appetite and not sleeping well (25%-57%). The other half of the unbearable aspects involved the domains of function, personhood, environment, and nature and prognosis of disease. The most frequent unbearable aspects were impaired activities, feeling dependent, help needed with housekeeping, not being able to do important things, trouble accepting the situation, being bedridden and loss of control (27%-55%). The combination of love and support was the most frequent source (67%) providing strength to bear suffering.</p> <p>Conclusions</p> <p>Overall unbearable suffering occurred in one in every four end-of-life cancer patients. Half of the unbearable aspects involved medical symptoms, the other half concerned psychological, social and existential dimensions. Physicians need to comprehensively assess suffering and provide psychosocial interventions alongside physical symptom management.</p