3,735 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
Feasibility study for a model independent measurement of 2 in decays using final states
In this paper we present a feasibility study for measuring the combination of
the Unitarity Triangle angle 2 with a time dependent Dalitz
analysis in decays using final states following the
method proposed in [1]. For this study we build a model for this decay using
the latest experimental information and we investigate the possibility of
fitting together with 2 all the relevant strong amplitudes and
phases of the decay model.
[1] R. Aleksan, T.C. Petersen and A. Soffer, Phys. Rev. D67 (2003) 096002
[hep-ph/0209194].Comment: 14 page
Unitarity Triangle Analysis in the Standard Model and Sensitivity to New Physics
By using the most recent determinations of the several theoretical and
experimental input parameters, we update the Unitarity Triangle analysis in the
Standard Model and discuss the sensitivity to New Physics effects. We
investigate the interest of measuring with a better precision the various
physical quantities entering the Unitarity Triangle analysis and study in a
model independent way whether, despite the undoubted success of the CKM
mechanism in the Standard Model, the Unitarity Triangle analysis still allows
the presence of New Physics.Comment: Invited talk at the Workshop on the CKM Unitarity Triangle, IPPP
Durham, April 2003 (eConf C0304052). 9 pages LaTeX, 15 eps figures. Misprint
corrected and references adde
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
2000 CKM-Triangle Analysis A Critical Review with Updated Experimental Inputs and Theoretical Parameters
Within the Standard Model, a review of the current determination of the sides
and angles of the CKM unitarity triangle 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 in September 2000. Results from the
experimental search for {B}^0_s-\bar{B}^0_s oscillations are introduced in the
present analysis using the likelihood. Special attention is devoted to the
determination of the theoretical uncertainties. The purpose of the analysis is
to infer regions where the parameters of interest lie with given probabilities.
The BaBar "95 %, C.L. scanning" method is also commented.Comment: 44 pages (revised version
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
Long-term effects of automated mechanical peripheral stimulation on gait patterns of patients with Parkinson's disease
New treatments based on peripheral stimulation of the sensory–motor system have been inspiring new rehabilitation approaches in Parkinson’s disease (PD), especially to reduce gait impairment, levodopa washout effects, and the incidence of falls. The aim of this study was to evaluate the change in gait and the clinical status of PD patients after six sessions of a treatment based on automated mechanical peripheral stimulation (AMPS). Eighteen patients with PD and 15 age-matched healthy individuals (control group) participated in this study. A dedicated medical device delivered the AMPS. PD patients were treated with AMPS six times once every 4 days. All PD patients were treated in the off-levodopa phase and were evaluated with gait analysis before and after the first intervention (acute phase), after the sixth intervention, 48 h after the sixth intervention, and 10 days after the end of the treatment. To compare the differences among the AMPS interventions (pre, 6 AMPS, and 10 days) in terms of clinical scales, a t-test was used (α≤0.05). In addition, to compare the differences among the AMPS interventions (pre, post, 6 AMPS, 48 h and 10 days), the gait spatiotemporal parameters were analyzed using the Friedman test and the Bonferroni post-hoc test (α≤0.05). Also, for comparisons between the PD group and the control group, the gait spatiotemporal parameters were analyzed using the Mann–Whitney test and the Bonferroni post-hoc test (α≤0.05). The results of the study indicate that the AMPS treatment has a positive effect on bradykinesia because it improves walking velocity, has a positive effect on the step and stride length, and has a positive effect on walking stability, measured by the increase in stride length. These results are consistent with the improvements measured with clinical scales. These findings indicate that AMPS treatment seems to generate a more stable walking pattern in PD patients, reducing the well-known gait impairment that is typical of PD; regular repetition every 4 days of AMPS treatment appears to be able to improve gait parameters, to restore rhythmicity, and to reduce the risk of falls, with benefits maintained up to 10 days after the last treatment. The trial was registered online at ClinicalTrials.gov (number identifier: NCT0181528)
- …