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Register a new userReview of Recent Measurements of the Sides of the CKM Unitarity Triangle
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Giampiero Mancinelli
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We give a review of the status of the global effort to measure the sides of the CKM Unitarity Triangle.
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This report contains the results of the Workshop on the CKM Unitarity Triangle, held at CERN on 13-16 February 2002 to study the determination of the CKM matrix from the available data of K, D, and B physics. This is a coherent document with chapters covering the determination of CKM elements from tree level decays and K and B meson mixing and the global fits of the unitarity triangle parameters. The impact of future measurements is also discussed.
Some fine differences between the twin $b$-flavored unitarity triangles are calculated by means of a generalized Wolfenstein parametrization of the CKM matrix, and a possibility of experimentally establishing the second triangle is briefly discussed. We find that the apexes of these two triangles, characterized respectively by $(overline{rho}, overline{eta})$ and $(widetilde{rho}, widetilde{eta})$, are located on the same circular arc in the complex plane. This observation provides us with a new way to test consistency of the CKM picture of CP violation in the quark sector and probe possible new physics. The differences between the apexes (i.e., $widetilde{rho} - overline{rho}$ and $widetilde{eta} - overline{eta}$) are found to be of ${cal O}(lambda^2)$ with $lambda simeq 0.22$ being the Wolfenstein expansion parameter, and the shapes of these two triangles are found to be insensitive to the two-loop renormalization-group-equation running effects up to the accuracy of ${cal O}left(lambda^4right)$.
In the past 10 years our knowledge of the parameters rho and eta of the Cabibbo-Kobayashi-Maskawa matrix has improved substantially. This article reviews the measurements that contributed to this advance, and discusses their implication in terms of understanding CP violation in the Standard Model and beyond.
At the Tevatron Collider at Fermilab, a large number of top quarks have been produced in the ongoing run. The CDF and DZero collaborations have made first measurements of the ttbar cross section in several decay channels, and have measured the top quark mass. In addition, they have set new limits on the cross sections for single top quark production, and have started to measure some of the properties of the top quark via studies of its decays. This paper summarizes the status of these measurements and discusses where they are heading in the next few years. The paper is based on a talk I gave at the Rencontres du Vietnam in Hanoi, August 2004; the results have been updated to show the latest values and new measurements.
We present an update of the Unitarity Triangle (UT) analysis, within the Standard Model (SM) and beyond. Within the SM the main novelties are the inclusion in epsilon_K of the contributions of xi and phi_epsilon eq pi/4 pointed out by A.J. Buras and D. Guadagnoli, and an accurate prediction of BR(B -> tau nu), by using the indirect determination of |V_ub| from the UT fit, which can be compared to the present experimental result. In the generalization of the UT analysis to investigate New Physics (NP) effects, the estimate of xi is more delicate and only the effect of phi_epsilon eq pi/4 has been included. We confirm an hint of NP in the B_s-bar B_s mixing at the 2.9 sigma level, which makes a comparison with new experimental data certainly desired.
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