14,404 research outputs found
Supersymmetric contributions to B --> K \pi branching ratio
We analyze the supersymmetric contributions to the B --> K\pi process. We
show that the simultaneous contributions from the penguin diagrams with
chargino and gluino in the loop could lead to a possible solution to the B -->
K \pi puzzle. Our result indicates that including the stringent constraint from
the b --> s \gamma branching ratio, the supersymmeteric models with light
right-handed top-squark and large mixing between second and third generation of
up and down squarks is the most preferred by the current experimental data.Comment: 4 pages, revtex, 2 figure
Thermal response of large area high temperature superconducting YBaCuO infrared bolometer
Thermal analysis of large area high temperature superconducting infrared detector operating in the equilibrium mode (bolometer) was performed. An expression for the temperature coefficient beta=1/R(dR/dT) in terms of the thermal conductance and the thermal time constant of the detector were derived. A superconducting transition edge bolometer is a thermistor consisting of a thin film superconducting YBaCuO evaporated into a suitable thermally isolated substrate. The operating temperature of the bolometer is maintained close to the midpoint of the superconducting transition region where the resistance R has a maximum dynamic range. A detector with a strip configuration was analyzed and an expression for the temperature rise (delta T) above the ambient due to a uniform illumination with a source of power density P(sub i) was calculated. An expression for the thermal responsivity of the detector was derived using the thermal diffusion analysis with appropriate boundary conditions. It was found that the thermal responsibility depends upon the spatial modulation frequency and the angular frequency of the incoming radiation. The problem of the thermal cross talk between different detector elements was addressed. In the case of monolithic HTS detector array with a row of square elements of dimensions 2a and CCD or CID readout electronics the thermal spread function was derived for different spacing between elements. This analysis can be critical for future design and applications of large area focal plane arrays as broad band optical detectors made of granular thin films HTS YBaCuO
Supersymmetric Models and CP violation in B decays
In this talk CP violation in the supersymmetric models, and especially in
B-decays is discussed. We review our analysis of the supersymmetric
contributions to the mixing CP asymmetries of and processes. Both gluino and chargino exchanges are considered
in a model independent way by using the mass insertion approximation method.
The QCD factorization method is used, and parametrization of this method in
terms of Wilson coefficients is presented in both decay modes. Correlations
between the CP asymmetries of these processes and the direct CP asymmetry in
decay are shown.Comment: 16 pages, 7 figures. Prepared for the proceedings of the 1st GUC
workshop on High Energy Physics, Cairo, Jan 9-13, 200
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Using a smartphone app to identify signs of pre-eclampsia and/or worsening blood pressure
Background
Hypertensive disorders of pregnancy complicate 10% of pregnancies and can have serious consequences.
Aims
To explore the experiences of pregnant women with a history of hypertension using an innovative home blood pressure monitoring device.
Methods
A qualitative study using a grounded theory approach was undertaken. Data were collected through semi-structured interviews. Women were given a blood pressure machine to monitor their blood pressure daily. They inserted their blood pressure results on a smartphone app and answered questions for signs of pre-eclampsia. Participants were followed up every 2 weeks.
Findings
The results suggested that women wanted a holistic care pathway for the management of hypertension in pregnancy. Three subcategories (‘empowerment’, ‘comparison of care pathways’ and ‘continuity of care’) were also identified.
Conclusions
The traditional management of hypertension in pregnancy is not holistic. The home blood pressure service was accepted by women and incorporated elements of holistic care but more is required to meet the standard of care that women need
B_s^0 - bar{B}_s^0 Mixing and the B_s -> J/psi phi Asymmetry in Supersymmetric Models
We analyse supersymmetric contributions to B_s mixing and their impact on
mixing-induced CP asymmetries, using the mass insertion approximation. We
discuss in particular the correlation of SUSY effects in the CP asymmetries of
B_s -> J/psi phi and B_d -> phi K_S and find that the mass insertions dominant
in B_s mixing and B_d -> phi K_S are (delta_{23}^d)_{LL, RR} and
(delta_{23}^d)_{LR, RL}, respectively. We show that models with dominant
(delta_{23}^d)_{LR, RL} can accomodate a negative value of S_{phi K_S}, in
agreement with the BELLE measurement of that observable, but yield a B_s mixing
phase too small to be observed. On the other hand, models with dominant
(delta_{23}^d)_{LL, RR} predict sizeable SUSY contributions to both Delta M_s
and the mixing phase, but do not allow the asymmetry in B_d -> phi K_S to
become negative, except for small values of the average down squark mass,
which, in turn, entail a value of Delta M_s too large to be observed at the
Tevatron and the LHC. We conclude that the observation of B_s mixing at hadron
machines, together with the confirmation of a negative value of S_{phi K_S},
disfavours models with a single dominant mass insertion.Comment: 17 pages, 5 figure
Dark Matter in B-L Extended MSSM Models
We analyze the dark matter problem in the context of supersymmetric
U(1)_{B-L} model. In this model, the lightest neutalino can be the B-L gaugino
widetilde {Z}_{B-L} or the extra Higgsinos widetilde{chi}_{1,2} dominated. We
compute the thermal relic abundance of these particles and show that, unlike
the LSP in MSSM, they can account for the observed relic abundance with no
conflict with other phenomenological constraints. The prospects for their
direct detection, if they are part of our galactic halo, are also discussed.Comment: 11 pages, 9 figures. Published versio
A possible supersymmetric solution to the discrepancy between B -> \phi K_S and B -> \eta' K_S CP asymmetries
We present a possible supersymmetric solution to the discrepancy between the
observed mixing CP asymmetries in B -> \phi K_S and B -> \eta' K_S. We show
that due to the different parity in the final states of these processes, their
supersymmetric contributions from the R-sector have an opposite sign, which
naturally explain the large deviation between S_{\phi K_S} and S_{\eta' K_S}.
We also consider the proposed mechanisms to solve the puzzle of the observed
large branching ratio of B -> \eta' K and study their impact on S_{eta' K_S}.Comment: 4 pages, 2 figure
Chargino contributions to the CP asymmetry in B -> Phi K(S) decay
We perform a model independent analysis of the chargino contributions to the
CP asymmetry in B -> Phi K(S) process. We use the mass insertion approximation
method generalized by including the possibility of a light right-stop. We find
that the dominant effect is given by the contributions of the mass insertions
deltaU_LL(32) and deltaU_RL(32) to the Wilson coefficient of the chromomagnetic
operator. By considering both these contributions simultaneously, the CP
asymmetry in B -> Phi K(S) process is significantly reduced and negative
values, which are within the 1-sigma experimental range and satisfy the b -> s
gamma constraints, can be obtained.Comment: 14 pages, LaTeX, 3.eps Figure
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