We calculate the decay width of h0→bb‾ in the Minimal Supersymmetric Standard Model (MSSM) with quark-flavour violation (QFV) at full one-loop level. The effect of c˜−t˜ mixing and s˜−b˜ mixing is ...studied taking into account the constraints from the B-meson data. We discuss and compare in detail the decays h0→cc‾ and h0→bb‾ within the framework of the perturbative mass insertion technique using the Flavour Expansion Theorem. The deviation of both decay widths from the Standard Model results can be quite large. While in h0→cc‾ it is almost entirely due to the flavour violating part of the MSSM, in h0→bb‾ it is mainly due to the flavour conserving part. Nevertheless, Γ(h0→bb‾) can fluctuate up to ∼7% due to QFV chargino exchange with large c˜−t˜ mixing.
Background. Neurodevelopmental outcome after neonatal arterial switch operation for complete transposition of the great arteries is an important topic needing prospective assessment.
Methods. A group ...of 33 unselected children (3.0 to 4.6 years) operated on as neonates with combined deep hypothermic circulatory arrest and low flow cardiopulmonary bypass and a control group of 32 age-matched healthy children (3.0 to 4.8 years) underwent evaluation of socioeconomic and clinical neurological status and a standardized test comprising all areas of child development. Results of patients were related to those of the control group, to population norms, and to preoperative, perioperative, and postoperative cerebral risk factors.
Results. Clinical neurological status was normal in 26 patients (78.8%) and reduced in 7 (21.2%). Complete developmental score and the subscores for motor function, visual perception, learning and memory, cognitive function, language, and socioemotional functions were not different compared to population norms. Compared to the patients, the children of the control group scored higher on tests of complete development, cognition, and language, but also on socioeconomic status. Complete developmental score and the scores for motor, cognitive, and language functions were weakly inversely related to the duration of circulatory arrest, but not to the duration of bypass. Cerebral risk factors such as serum levels of the neuron-specific enolase, perinatal acidosis, perinatal asphyxia, peri- and postoperative cardiocirculatory insufficiency, or clinical seizures were not correlated to the test results.
Conclusions. Neonatal arterial switch operation with combined circulatory arrest and low flow bypass is associated with neurological impairment, but not with reduced development as assessed by formal testing of motor, cognitive, language, and behavioral functions. Perioperative serum level of the neuron-specific enolase is not a valid marker for later developmental impairment.
We calculate the supersymmetric
O
(α
s) QCD corrections to the decays
q
i → q′
χ
j
±
(
i,
j = 1, 2) and
q
i → q
χ
k
0
(
k = 1,…, 4) within the Minimal Supersymmetric Standard Model. In particular we ...consider the decays of squarks of the third generation,
t
i
and
b
i
(
i = 1, 2), where the left-right mixing must be taken into account. The corrections turn out to be of about 10%, except for higgsino-like charginos or neutralinos, where they can go up to 40%.
The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics ...return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.
We study the production of charginos \(e^+ e^- \to\tilde{\chi}^{+}_i\tilde{\chi}^{-}_j, (i,j=1,2)\) with polarized beams and the subsequent decays \(\tilde{\chi}^{+}_{i} \to \tilde{\chi}^0_k ...\ell^{+}\nu_\ell\) and \(\tilde{\chi}^{-}_{j} \to \tilde{\chi}^0_l \ell^{-}\bar{\nu}_\ell, (k,l=1,\ldots,4)\), including the complete spin correlations between production and decay. Analytical formulae are presented for the joint spin-density matrix of the charginos, for the chargino decay matrix and for the differential cross section of the combined processes of production and decays. We present numerical results for pair production of the lighter chargino with unpolarized beams and the leptonic decay of \(\tilde{\chi}_1^-\) into the lightest neutralino \(\tilde{\chi}^0_1\). The lepton angular distribution and the forward-backward asymmetry are studied in four representative scenarios for \(\sqrt{s}=192\) GeV and \(\sqrt{s}=200\) GeV.
We show that the Higgs boson exchange contribution can be large in three-body decays of neutralinos even in the case of small tan
β. This enlarges the branching ratios for the decays
χ
̃
0
2→
χ
̃
0
1
...b
b
̄
and
χ
̃
0
2→
χ
̃
0
1
τ
−τ
+
. This is the case in the region of the parameter space where the two lightest neutralinos are gaugino-like, the sfermions are heavier than 300 GeV, and
m
A
0
≲200 GeV.
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