Implications of recent measurements of hadronic charmless B decays - art. no. 054029

The implications of recent CLEO measurements of hadronic charmless B decays are discussed. (i) Employing the Bauer-Stech-Wirbel (BSW) model for form f actors as a benchmark, the B-->pi(+)pi(-) data indicate that the form facto r F-o(B pi)(0) is smaller than that predicted by the BSW model, whereas the data of B-->omega pi, K* eta imply that the form factors A(o)(B omega)(0), A(o)(BK*)(0) are greater than the BSW model values. (ii) The tree-dominate d modes B-->pi(+)pi(-), rho(o)pi(+/-), omega pi(+/-) imply that the effecti ve number of colors N-c(eff)(LL) for (V-A)(V-A) operators is preferred to b e smaller, while the current limit on B-->phi K shows that N-c(eff)(LR) >3. The data of B-->K eta' and K*eta clearly indicate that N-c(eff)(LR)>>N-c(e ff)(LL). (iii) in order to understand the observed suppression of pi(+)pi(- ) and nonsuppression of K pi modes, both bring governed by the form factor F-o(B pi), the unitarity angle gamma is preferred to be greater than 90 deg rees. By contrast, the new measurement of B+/- -->rho(o)pi(+/-) no longer s trongly favors cos gamma<0. (iv) The observed pattern K(-)pi(+)-(K) over ba r(o)pi(-)similar to 2/3K(-)pi(o) is consistent with thr theoretical expecta tion: The constructive interference between electroweak and QCD penguin dia grams in the K(-)pi(o) mode explains why B(B--->K(-)pi(o))>1/2 B((B) over b ar(o)--> K(-)pi(+)). (v) The observation N-c(eff)(LL) <3 <N-c(eff)(LR) and our preference for N-c(eff)(LL)similar to 2 and N-c(eff)(LR)similar to 6 ar e justified by a recent perturbative QCD calculation of hadronic rare B dec ays in the heavy quark limit. (vi) The sizable branching ratios of K* eta a nd the enormously large decay rates of K eta' indicate that it is the const ructive interference of two comparable penguin amplitudes rather than the m echanism specific to the eta' that accounts for the bulk of B --> eta'K and eta K* data. (vii) The new upper limit set for B--->omega K- no longer imp oses a serious problem for the factorization approach. It is anticipated th at B(B--->omega K-)greater than or similar to 2B(B--->rho(o)K(-))similar to 2x 10(-6). (viii) An improved and refined measurement of B-K*- pi(+), (K) over bar(o)pi(o) is called for in order to resolve the discrepancy between theory and experiment. Theoretically, it is expected (K) over bar(o)pi(o) s imilar to 1/2 K(-)pi(o) and K- pi(+) similar to 3 K(*-)pi(+).