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A bound on the angle gamma of the unitarity triangle is derived using experimental information on the CP-averaged branching ratios for the rare decays B^+- -> pi^+- K^0 and B^+- -> pi^0 K^+-. The theoretical description is cleaner than the…

High Energy Physics - Phenomenology · Physics 2010-11-23 M. Neubert , J. L. Rosner

In charmless nonleptonic B decays to \pi\pi or \rho\rho, the "color allowed" and "color suppressed" tree amplitudes can be studied in a systematic expansion in \alphas(mb) and \Lambda/mb. At leading order in this expansion their relative…

High Energy Physics - Phenomenology · Physics 2014-11-18 Yuval Grossman , Andreas Hocker , Zoltan Ligeti , Dan Pirjol

In the recent literature, constraints on the CKM angle $\gamma$ arising from the branching ratios for $B^\pm\to\pi^\pm K$ and $B_d\to\pi^\mp K^\pm$ decays received a lot of attention. An important theoretical limitation of the accuracy of…

High Energy Physics - Phenomenology · Physics 2009-10-30 Andrzej J. Buras , Robert Fleischer , Thomas Mannel

Establishing CP violation in B0 (bar{B0}) --> l+ l- decays requires a measurement of polarization of the final lepton pair, or a precise determination of the B0 --> l+ l- and bar{B0} --> l+ l- rates. We first argue that if the amplitudes of…

High Energy Physics - Phenomenology · Physics 2014-11-18 Piotr H. Chankowski , Jan Kalinowski , Zbigniew Was , Malgorzata Worek

The Standard-Model interpretation of the ratios of charged and neutral B-> pi K rates, R_c and R_n, respectively, points towards a puzzling picture. Since these observables are affected significantly by colour-allowed electroweak (EW)…

High Energy Physics - Phenomenology · Physics 2016-09-06 Andrzej J. Buras , Robert Fleischer , Stefan Recksiegel , Felix Schwab

Defining a most economical parametrization of time-dependent B-> rho^\pm pi^\mp decays, including a measurable phase alpha_{eff} which equals the weak phase alpha in the limit of vanishing penguin amplitudes, we propose two ways for…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. Gronau , J. Zupan

Using a data sample of 122 million Upsilon(4S) -> BBbar decays collected with BaBar detector at the PEP-II asymmetric B factory at SLAC, we measure the time-dependent-asymmetry parameters of the longitudinally polarized component in the B0…

High Energy Physics - Experiment · Physics 2009-04-02 Haibo Li

We present an improved measurement of the standard model CP violation parameter sin2phi_1 (also known as sin2beta) based on a sample of 85 times 10^6 B Bbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB…

High Energy Physics - Experiment · Physics 2008-11-26 The Belle Collaboration , K. Abe

Recent experimental observations of CP asymmetry in B0 -> psi K0 constitute the first significant signal of CP violation outside the neutral kaon system; thus they represent an important milestone to test the CKM paradigm. We, therefore,…

High Energy Physics - Phenomenology · Physics 2014-11-17 David Atwood , Amarjit Soni

Neglecting smaller amplitudes the time-dependent CP asymmetry in penguin-dominated b -> s q \bar q transitions (such as B -> phi K_S) is expected to equal sin(2 beta), an expectation not borne out by the present average experimental data. I…

High Energy Physics - Phenomenology · Physics 2010-04-05 M. Beneke

The $b \to s$ penguin amplitude affects a number of $B$ meson decays to two pseudoscalar ($P$) mesons in which potential anomalies are being watched carefully, though none has yet reached a statistically compelling level. These include (a)…

High Energy Physics - Phenomenology · Physics 2014-11-18 Michael Gronau , Jonathan L. Rosner

We analyze the deviations of the mixing induced CP asymmetry in B-->phi Ks from sin(2beta), as well as the deviations of the asymmetries in Bs-->K*K*, Bs-->phi K* and Bs-->phi phi from sin(2beta_s), that arise in SM due to penguin…

High Energy Physics - Phenomenology · Physics 2011-03-23 Javier Virto

The recent observation of B_d -> pi^0 pi^0 at the B factories with a surprisingly large branching ratio represents a challenge for theory, and complements the amazingly small B_d -> pi^+ pi^- rate. We point out that all puzzling B -> pi pi…

High Energy Physics - Phenomenology · Physics 2009-11-10 Andrzej J. Buras , Robert Fleischer , Stefan Recksiegel , Felix Schwab

Using the $SU(3)$ flavour symmetry of strong interactions, we propose strategies for extracting both the CKM-angle $\gamma$ and the $\bar b\to\bar uu\bar s$ tree-level amplitude $T'$. We present also an approximate approach using the…

High Energy Physics - Phenomenology · Physics 2011-01-05 Robert Fleischer

We report the observation of the b -> d penguin-dominated decay B0 -> K*0 K*0bar with a sample of 383.2 +/- 4.2 million BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e^+e^- collider at the Stanford Linear…

High Energy Physics - Experiment · Physics 2010-04-12 The BABAR Collaboration , B. Aubert

A reliable prediction for $CP$ violation in $B^{0}_{d}$ vs $\bar{B}^{0}_{d}\rightarrow \pi^{+}\pi^{-}$ suffers from the penguin-diagram induced uncertainty. With the help of SU(3) relations, we show that both the magnitude and strong phase…

High Energy Physics - Phenomenology · Physics 2010-11-01 Zhi-zhong Xing

We study the determination of gamma from CP-violating observables in B -> pi+ pi- and B -> psi K_S. This determination requires theoretical input to one combination of hadronic parameters. We show that a mild assumption about this quantity…

High Energy Physics - Phenomenology · Physics 2009-11-10 F. J. Botella , Joao P. Silva

We present updated measurements of the branching fractions and CP asymmetries for B0 -> pi0 pi0, B+ -> pi+ pi0, and B+ -> K+ pi0. Based on a sample of 383 x 10^6 Upsilon(4S) -> B Bbar decays collected by the BABAR detector at the PEP-II…

High Energy Physics - Experiment · Physics 2010-04-12 The BABAR Collaboration , B. Aubert

We reanalyze the decay $B_d\to\pi^+\pi^-$ without assuming dominance of QCD penguins with internal top-quark exchanges. In that case the weak phase of the $\bar b \to\bar d$ QCD penguin amplitude is not related in a simple way to the CKM…

High Energy Physics - Phenomenology · Physics 2009-10-28 Robert Fleischer , Thomas Mannel

A major problem in the determination of the the CP angle $\alpha$, that should be measured through modes of the type $B_d, \bar{B}_d \to \pi \pi , \cdots ,$ is the uncertainty coming from Penguin diagrams. We consider the different ground…

High Energy Physics - Phenomenology · Physics 2009-10-28 R. Aleksan , F. Buccella , A. Le Yaouanc , L. Oliver , O. Pène , J. -C. Raynal