3,144 research outputs found
Constraints on the parameters of the CKM matrix by End 1998
A review of the current status of the Cabibbo-Kobayashi-Maskawa matrix (CKM)
is presented. This paper is an update of the results published in [1]. The
experimental constraints imposed by the measurements of \epsilon_K,
V_{ub}/V_{cb}, \Delta m_d and from the limit on \Delta m_d are used. Values of
the constraints and of the parameters entering into the constraints, which
restrict the range of the \bar{\rho} and \bar{\eta} parameters, include recent
measurements presented at 1998 Summer Conferences and progress obtained by
lattice QCD collaborations. The results are: \bar{\rho}=0.202
^{+0.053}_{-0.059},\bar{\eta}=0.340 \pm 0.035, from which the angles \alpha,
\beta and \gamma of the unitarity triangle are inferred : \sin 2 \alpha = -0.26
^{+ 0.29}_{-0.28} ,\sin 2 \beta = 0.725 ^{+0.050}_{-0.060} ,\gamma=
(59.5^{+8.5}_{-7.5})^{\circ}. Without using the constraint from \epsilon_K,
\sin 2 \beta has been obtained: \sin 2 \beta = 0.72 ^{+0.07}_{-0.11}. Several
external measurements or theoretical inputs have been removed, in turn, from
the constraints and their respective probability density functions have been
obtained. Central values and uncertainties on these quantities have been
compared with actual measurements or theoretical evaluations. In this way it is
possible to quantify the importance of the different measurements and the
coherence of the Standard Model scenario for CP violation. An important result
is that \Delta m_s is expected to be between [12.0-17.6] ps^{-1} with 68% C.L.
and <20 ps^{-1} at 95% C.L. Finally relations between the CKM parameters and
the quark masses are examined within a given model.Comment: 26 page
Investigating The Physics Case of Running a B-Factory at the Y(5S) Resonance
We discuss the physics case of a high luminosity B-Factory running at the
Y(5S) resonance. We show that the coherence of the B meson pairs is preserved
at this resonance, and that Bs can be well distinguished from Bd and charged B
mesons. These facts allow to cover the physics program of a traditional
B-Factory and, at the same time, to perform complementary measurements which
are not accessible at the Y(4S). In particular we show how, despite the
experimental limitations in performing time-dependent measurements of Bs
decays, the same experimental information can be extracted, in several cases,
from the determination of time-integrated observables. In addition, a few
examples of the potentiality in measuring rare Bs decays are given. Finally, we
discuss how the study of Bs meson will improve the constraints on New Physics
parameters in the Bs sector, in the context of the generalized Unitarity
Triangle analysis.Comment: 47 pages, 22 figure
Determination of the CKM unitarity triangle parameters by end 1999
Within the Standard Model, a review of the current determination of the CKM
unitarity triangle parameters is presented, using experimental constraints from
the measurements of |epsilon_K|, V_ub/V_cb, Delta m_d and from the limit on
Delta m_s, available by end 1999.Comment: Talk given by A. Stocchi at the Third International Conference on B
physics and CP violation, National Taiwan Univ., Taipei, Tawain, December
3-7, 199
Constraints on the parameters of the matrix at the end of 1997
A review of the current status of the Cabibbo-Kobayashi-Maskawa matrix V_CKM
is presented. This paper contains an update of the results published in
hep-ph/9711261. Values of the parameters entering into the constraints, which
restrict the range for rho and eta parameters, include recent measurements
given at 1997 Summer Conferences and progress obtained by lattice QCD
collaborations.Experimental constraints imposed by the measurements of
epsilon_k,V_ub/V_cb, Delta m_d and by the limit on Delta m_s, are compatible
and do not show evidence for New Physics inside measurements errors. Values for
the angles alpha, beta and gamma of the C.K.M. triangle have been also
obtained: rho=0.156 +- 0.090, eta=0.328 +- 0.054 sin 2alpha = -0.10+-0.40, sin
2beta = 0.68 +- 0.10, gamma= 64+-12 Angles theta,theta_u,theta_d and phi
proposed in the parametrisation (Phys. Lett. B5353 (1995) 114.) of the C.K.M.
matrix have been also determined. Finally, as there are more constraints than
the fitted rho and eta parameters, several external measurements or theoretical
inputs have been removed, in turn, from the constraints and their respective
values have been fitted simultaneously with rho and eta.Central values and
uncertainties on these quantities have been compared with actual measurements
or theoretical evaluations. In this way it is possible to quantify the
importance of the different measurements and the coherence of the Standard
Model scenario for CP violation.Comment: 29 page
A proposal for a comprehensive grading of Parkinson's disease severity combining motor and non-motor assessments: meeting an unmet need.
Non-motor symptoms are present in Parkinson's disease (PD) and a key determinant of quality of life. The Non-motor Symptoms Scale (NMSS) is a validated scale that allows quantifying frequency and severity (burden) of NMS. We report a proposal for using NMSS scores to determine levels of NMS burden (NMSB) and to complete PD patient classification
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