Implications of unitarity and precision measurements on CKM matrix elements

Gulsheen Ahuja, Manmohan Gupta, Sanjeev Kumar, Monika Randhawa

Published 2006-08-07, updated 2006-12-12Version 2

Unitarity along with precision measurements of sin2\beta, V_{us} and V_{cb} allows one to find a lower bound V_{ub}\geq 0.0035 which, on using the recently measured angle \alpha of the unitarity triangle, translates to V_{ub}= 0.0035\pm 0.0002. This precise value, stable for a good deal of changes in \alpha, along with CP violating phase \delta found from unitarity allows the construction of a `precise' CKM matrix. The above unitarity based value of V_{ub} is in agreement with the latest exclusive value used as input by UTfit, CKMfitter, HFAG, however underlines the so called `tension' faced by the latest inclusive V_{ub}=0.00449 \pm 0.00033. Further, using this inclusive value of V_{ub} along with the latest sin2\beta, one finds \delta=23 ^{\rm o}- 39 ^{\rm o}, again in conflict with \delta measured in B-decays. The calculated ranges of the elements of the CKM matrix are in excellent agreement with those obtained recently by UTfit, CKMfitter and HFAG. Also, the ratio \frac{V_{ts}}{V_{td}} is in agreement with its latest measured value, whereas there is some disagreement between the `measured' and the calculated V_{td} values.