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ABSTRACT: We calculate the direct CP violating asymmetry parameter, $a_{CP}$, for $B \to \pi^{+} \pi^{-} \pi$ and $B \to \pi^{+} \pi^{-} K$ decays, in the case where $\rho^0-\omega$ mixing effects are taken into account. We find that the direct CP asymmetry for $B^{-} \to \pi^{+} \pi^{-} \pi^{-}$, $\bar{B}^{0} \to \pi^{+} \pi^{-}\pi^{0}$, $B^{-} \to \pi^{+} \pi^{-} K^{-}$ and $\bar{B}^{0} \to \pi^{+} \pi^{-}\bar{K}^{0}$, reaches its maximum when the invariant mass $\pi^{+} \pi^{-}$ is in the vicinity of the $\omega$ meson mass. The inclusion of $\rho^0-\omega$ mixing provides an opportunity to erase, without ambiguity, the phase uncertainty mod$(\pi)$ in the determination of the CKM angles $\alpha$ in case of $b\to u$ and $\gamma$ in case of $b \to s$. Comment: 5 pages, 1 figure. Talk given at the International Europhysics Conference on High Energy Physics, July 21st - 27th 2005, Lisboa, Portugal
01/2006;
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ABSTRACT: We investigate the chiral extrapolation of the lattice data for the light-heavy meson hyperfine splittings D^*-D and B^*-B to the physical region for the light quark mass. The chiral loop corrections providing non-analytic behavior in m_\pi are consistent with chiral perturbation theory for heavy mesons. Since chiral loop corrections tend to decrease the already too low splittings obtained from linear extrapolation, we investigate two models to guide the form of the analytic background behavior: the constituent quark potential model, and the covariant model of QCD based on the ladder-rainbow truncation of the Dyson-Schwinger equations. The extrapolated hyperfine splittings remain clearly below the experimental values even allowing for the model dependence in the description of the analytic background. Comment: 14 pages, 4 figures, typos corrected, presentation clarified
11/2005;
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ABSTRACT: A complete study of the process B to pi+ pi- V(V=1--) is performed both in the framework of the helicity formalism and the effective lagrangian approach. Emphasis is put on the factorization hypothesis and the importance of the rho0- omega mixing in enhancing the direct CP violation. New results involving some branching ratios and the ratio of the Penguin/Tree amplitude are given in details.
12/2004;
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ABSTRACT: The $B \to \pi$ and $B \to K$ transitions involved in hadronic B decays are investigated in a phenomenological way through the framework of QCD factorization. By comparing our results with experimental branching ratios from the BELLE, BABAR and CLEO Collaborations for all the B decays including either a pion or a kaon, we propose boundaries for the transition form factors $B \to \pi$ and $B \to K$ depending on the CKM matrix element parameters $\rho$ and $\eta$. From this analysis, the form factors required to reproduce the experimental data for branching ratios are $F^{B \to \pi}= 0.31 \pm 0.12$ and $F^{B \to K}= 0.37\pm 0.13$. We calculate the direct CP violating asymmetry parameter, $a_{CP}$, for $B \to \pi^{+} \pi^{-} \pi$ and $B \to \pi^{+} \pi^{-} K$ decays, in the case where $\rho-\omega$ mixing effects are taken into account. Based on these results, we find that the direct CP asymmetry for $B^{-} \to \pi^{+} \pi^{-} \pi^{-}$, $\bar{B}^{0} \to \pi^{+} \pi^{-} \pi^{0}$, $B^{-} \to \pi^{+} \pi^{-} K^{-}$, and $\bar{B}^{0} \to \pi^{+} \pi^{-} \bar{K}^{0}$, reaches its maximum when the invariant mass $\pi^{+} \pi^{-}$ is in the vicinity of the $\omega$ meson mass. The inclusion of $\rho-\omega$ mixing provides an opportunity to erase, without ambiguity, the phase uncertainty mod$(\pi)$ in the determination of the CKM angles $\alpha$ in case of $b\to u$ and $\gamma$ in case of $b \to s$. Comment: 74 pages, 15 figures, 8 tables. A few misprints corrected, two references added
11/2004;
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ABSTRACT: Simulation methods for the decays $ B \to {\pi}^+ {\pi}^- V$, where $V$ is a $1^{--}$ vector-meson, are presented in detail. Emphasis is put on the use of the helicity formalism and the use of effective Lagrangians. We show the importance of ${{\rho}^{0}}-{\omega}$ mixing in enhancing the direct $CP$ violation (DCPV) when the pion-pion invariant mass is near the mass of the $\omega$.
12/2003;
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ABSTRACT: Direct CP violation in the hadronic decays
\BarB0 ® p + p- p0\Bar{B}^{0} \rightarrow \pi^{ + }\pi^{-} \pi^{0}
is investigated near the peak of the
r0\rho^{0}
, taking into account the effect of
r\rho
-
w \omega
mixing. The branching ratios for the processes
B±,0 ® r±,0p±,0B^{\pm,0} \rightarrow \rho^{\pm,0}\pi^{\pm,0}
and
B- ® wp-B^{-} \rightarrow \omega \pi^{-}
are calculated as well. We find that the CP violating asymmetry is strongly dependent on the CKM matrix elements. For a fixed N
c
eff, the CP violating asymmetry, a
CP
, has a maximum of order
-40%-40\%
to
- 70%- 70\%
for
\BarB0 ® r0(w) p0\Bar{B}^{0} \rightarrow \rho^{0}(\omega) \pi^{0}
when the invariant mass of the
p + p-\pi^{ + }\pi^{-}
pair is in the vicinity of the
w \omega
resonance. The sensitivity of the asymmetry to N
c
eff is small in that case. Moreover, we find that in the range of N
c
eff which is allowed by the most recent experimental branching ratios from the BABAR, BELLE and CLEO Collaborations, the sign of
sind\sin \delta
is always positive. Thus, a measurement of direct CP violation in the decays
\BarB0 ® p + p- p0\Bar{B}^{0} \rightarrow \pi^{ + }\pi^{-} \pi^{0}
would remove the
\mod(p)\mod(\pi)
ambiguity in the determination of the CP violating phase angle
a\alpha
.
European Physical Journal C 10/2003; 31(2):215-226. · 3.63 Impact Factor
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ABSTRACT: Based on the QCD factorization approach we analyse the branching ratios for the channel $B \to \rho \pi$. From the comparisons with experimental data provided by CLEO, BELLE and BABAR we constrain the form factor $F^{B \to \pi}(m_{\rho}^{2})$ and propose boundaries for this form factor depending on the CKM matrix element parameters $\rho$ and $\eta$. Comment: 11 pages, 9 figures. Talk presented at Fourth Tropical Workshop, Cairns, Australia, 9--13 June 2003. Proceedings to be published by AIP
07/2003;
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ABSTRACT: We present a detailed study of direct CP violation and the branching ratios in the channels , where V is a vector meson ( or ). Emphasis is put upon the important role played by - mixing effects in the estimation of the CP-violating asymmetry parameter, aCP, associated with the difference of the B and decay amplitudes. A thorough study of the helicity amplitudes is presented as a function of the pion-pion invariant mass.
All of the calculations and simulations considered correspond to channels which will be analyzed at the LHCb facility.
European Physical Journal C 06/2003; 29(2):215-233. · 3.63 Impact Factor
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ABSTRACT: We present a detailed study of direct CP violation and branching ratios in the channels $B^{0,\pm} \to \pi^{+}\pi^{-} V^{0,\pm}$, where $V$ is a vector meson ($K^{* 0,\pm}$ or $\rho^{\pm}$). Emphasis is placed upon the important role played by ${{\rho}^{0}}-{\omega}$ mixing effects in the estimation of the CP-violating asymmetry parameter, $a_{cp}$, associated with the difference of $B$ and $\bar B$ decay amplitudes. A thorough study of the helicity amplitudes is presented as a function of the pion-pion invariant mass. All of the calculations and simulations considered correspond to channels which will be analyzed at the LHCb facility.
03/2003;
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ABSTRACT: Direct CP violation in the hadronic decays $\Bar{B}^{0} \to \pi^{+}\pi^{-} \pi^{0}$ is investigated near the peak of the $\rho^{0}$ taking into account the effect of $\rho - \omega$ mixing. Branching ratios for processes $B^{\pm,0} \to \rho^{\pm,0}\pi^{\pm,0}$ and $B^{-} \to \omega \pi^{-}$ are calculated as well. We find that the CP violating asymmetry is strongly dependent on the CKM matrix elements. For a fixed $N_{c}^{eff}$, the CP violating asymmetry, $a$, has a maximum of order -40% to -70% for $\Bar{B}^{0} \to \rho^{0}(\omega) \pi^{0}$ when the invariant mass of the $\pi^{+}\pi^{-}$ pair is in the vicinity of the $\omega$ resonance. The sensitivity of the asymmetry to $N_{c}^{eff}$ is small in that case. Moreover, we find that in the range of $N_{c}^{eff}$ which is allowed by the most recent experimental branching ratios from the BABAR, BELLE and CLEO Collaborations, the sign of $\sin \delta$ is always positive. Thus, a measurement of direct CP violation in decays $\Bar{B}^{0} \to \pi^{+}\pi^{-} \pi^{0}$ would remove the mod$(\pi)$ ambiguity in the determination of the CP violating phase angle $\alpha$. Comment: 23 pages, 10 figures, 5 tables. Misprints corrected and two figures updated
10/2002;
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ABSTRACT: The masses of heavy baryons containing a b quark have been calculated numerically in lattice QCD with pion masses which are much larger than its physical value. In the present work we extrapolate these lattice data to the physical mass of the pion by applying the effective chiral Lagrangian for heavy baryons, which is invariant under chiral symmetry when the light quark masses go to zero and heavy quark symmetry when the heavy quark masses go to infinity. A phenomenological functional form with three parameters, which has the correct behavior in the chiral limit and appropriate behavior when the pion mass is large, is proposed to extrapolate the lattice data. It is found that the extrapolation deviates noticably from the naive linear extrapolation when the pion mass is smaller than about 500MeV. The mass differences between Sigma_b and Sigma_b^* and between Sigma_b^{(*)} and Lambda_b are also presented. Uncertainties arising from both lattice data and our model parameters are discussed in detail. We also give a comparision of the results in our model with those obtained in the naive linear extrapolations. Comment: 29 pages, 9 figures
10/2002;
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ABSTRACT: We investigate in a phenomenological way, direct CP violation in the hadronic decays $B^{\pm,0} \to \pi^{+} \pi^{-} K^{\pm,0}$ where the effect of $\rho - \omega$ mixing is included. If $N_{c}^{eff}$ (the effective parameter associated with factorization) is constrained using the most recent experimental branching ratios (to $\rho^{0}K^{0}, \rho^{\pm}K^{\mp}, \rho^{\pm}K^{0}, \rho^{0} K^{\pm}$ and $\omega K^{\pm}$) from the BABAR, BELLE and CLEO Collaborations, we get a maximum CP violating asymmetry, $a_{max}$, in the range -25% to $+49%$ for $B^{-} \to \pi^{+}\pi^{-} K^{-}$ and -24% to $+55%$ for ${\Bar B}^{0} \to \pi^{+}\pi^{-} {\Bar K}^{0}$. We also find that CP violation is strongly dependent on the Cabibbo-Kobayashi-Maskawa matrix elements. Finally, we show that the sign of $\sin \delta$ is always positive in the allowed range of $N_{c}^{eff}$ and hence, a measurement of direct $CP$ violation in $B^{\pm,0} \to \pi^{+} \pi^{-} K^{\pm,0}$ would remove the mod$(\pi)$ ambiguity in ${\rm arg}[ - \frac{V_{ts}V_{tb}^{\star}}{V_{us}V_{ub}^{\star}}]$. Comment: 39 pages, 19 figures, 8 tables. Discussion added on Page 14. Misprints also corrected. To be published in Phys. Rev. D
08/2002;
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ABSTRACT: Hyperfine splittings between the heavy vector (D*, B*) and pseudoscalar (D, B) mesons have been calculated numerically in lattice QCD, where the pion mass (which is related to the light quark mass) is much larger than its physical value. Naive linear chiral extrapolations of the lattice data to the physical mass of the pion lead to hyperfine splittings which are smaller than experimental data. In order to extrapolate these lattice data to the physical mass of the pion more reasonably, we apply the effective chiral perturbation theory for heavy mesons, which is invariant under chiral symmetry when the light quark masses go to zero and heavy quark symmetry when the heavy quark masses go to infinity. This leads to a phenomenological functional form with three parameters to extrapolate the lattice data. It is found that the extrapolated hyperfine splittings are even smaller than those obtained using linear extrapolation. We conclude that the source of the discrepancy between lattice data for hyperfine splittings and experiment must lie in non-chiral physics. Comment: 27 pages, 6 figures
12/2001;
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ABSTRACT: We study direct CP violation in the hadronic decay $B^{\pm} \to \rho^{0}\pi^{\pm}$, including the effect of $\rho - \omega$ mixing. We find that the CP violating asymmetry is strongly dependent on the CKM matrix elements, especially the Wolfenstein parameter $\eta$. For fixed $N_{c}$ (the effective parameter associated with factorization), the CP violating asymmetry, $a$, has a maximum of order $30%-50%$ when the invariant mass of the $\pi^{+}\pi^{-}$ pair is in the vicinity of the $\omega$ resonance. The sensitivity of the asymmetry, $a$, to $N_{c}$ is small. Moreover, if $N_{c}$ is constrained using the latest experimental branching ratios from the CLEO collaboration, we find that the sign of $\sin \delta$ is always positive. Thus, a measurement of direct CP violation in $B^{\pm} \to \rho^{0}\pi^{\pm}$ would remove the mod$(\pi)$ ambiguity in ${\rm arg}[ - \frac{V_{td}V_{tb}^{\star}}{V_{ud}V_{ub}^{\star}}]$. Comment: 37 pages, 7 figures
09/2000;
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ABSTRACT: We study the possibility of obtaining large direct CP violation in the charmed hadron decays D+→ρ+ρ0(ω)→ρ+π+π-, D+→π+ρ0(ω)→π+π+π-, D0→φρ0(ω)→φπ+π-, D0→ηρ0(ω)→ηπ+π-, D0→η′ρ0(ω)→η′π+π-, D0→π0ρ0(ω)→π0π+π-, and Λc→pρ0(ω)→pπ+π- via ρ-ω mixing. The analysis is carried out in the factorization approach. The CP violation parameter depends on the effective parameter Nc which is relevant to the hadronization dynamics of each decay channel and should be determined by experiment. It is found that for fixed Nc the CP violation parameter reaches its maximum value when the invariant mass of the π+π- pair is in the vicinity of the ω resonance. For most of the parameter space explored the CP violating asymmetry is of order 10-4. However, over a small range, 1.98<~Nc<~1.99 and 1.95<~Nc<~2.02, the asymmetries for D0→π0ρ0(ω)→π0π+π- and Λc→pρ0(ω)→pπ+π- (respectively) can exceed 1%, at the cost of a small branching ratio. We also estimate the decay branching ratios for D0→π0ρ0 and Λc→pρ0 for these values of Nc, which should be tested by future experimental data.
Phys. Rev. D. 05/2000; 61(11).
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ABSTRACT: We study the possibility of obtaining large direct CP violation in the charmed hadron decays $D^+ \to \rho^+ \rho^0 (\omega) \to \rho^+ \pi^+\pi^-$, $D^+ \to \pi^+ \rho^0 (\omega) \to \pi^+ \pi^+\pi^-$, $D^0 \to \phi \rho^0 (\omega) \to\phi \pi^+\pi^-$, $D^0 \to\eta \rho^0 (\omega) \to\eta \pi^+\pi^-$, $D^0 \to \eta' \rho^0 (\omega) \to\eta' \pi^+\pi^-$, $D^0 \to \pi^0 \rho^0 (\omega) \to \pi^0 \pi^+\pi^-$, and $\Lambda_c \ra p \rho^0 (\omega) \to p \pi^+\pi^-$ via $\rho-\omega$ mixing. The analysis is carried out in the factorization approach. The CP violation parameter depends on the effective parameter, $N_{c}$, which is relevant to hadronization dynamics of each decay channel and should be determined by experiments. It is found that for fixed $N_{c}$ the CP violation parameter reaches its maximum value when the invariant mass of the $\pi^+\pi^-$ pair is in the vicinity of the $\omega$ resonance. For $D^0 \to \pi^0 \rho^0 (\omega) \to \pi^0 \pi^+\pi^-$ and $\Lambda_c \to p \rho^0 (\omega) \to p \pi^+\pi^-$ the maximum CP violating asymmetry is bigger than 1% when $1.98\leq N_c \leq 1.99$ and $1.95\leq N_c \leq 2.02$, respectively. We also estimate the decay branching ratios for $D^0 \to \pi^0 \rho^0$ and $\Lambda_c \to p \rho^0$ for these values of $N_c$, which should be tested by future experimental data. Comment: 25 pages, 2 figures
07/1999;
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ABSTRACT: We study direct CP violation in the bottom baryon decays Λb→fρ0(ω)→fπ+π- (f=n or Λ). It is found that in these decays via ρ-ω mixing the CP violation could be very large when the invariant mass of the π+π- pair is in the vicinity of the ω resonance. With a typical value Nc=2 in the factorization approach, the maximum CP-violating asymmetries are more than 50% and 68% for Λb→nπ+π- and Λb→Λπ+π-, respectively. With the aid of heavy quark symmetry and phenomenological models for the hadronic wave functions of Λb, Λ and the neutron, we estimate the branching ratios of Λb→n(Λ)ρ0.
Phys. Rev. D. 10/1998; 58(9).
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ABSTRACT: We study direct CP violation in the bottom baryon decays \Lambda_b -> f \rho^0 (\omega) -> f\pi^+\pi^- (f=n or \Lambda). It is found that in these decays via \rho-\omega mixing the CP violation could be very large when the invariant mass of the \pi^+\pi^- pair is in the vicinity of the \omega resonance. With a typical value N_c =2 in the factorization approach, the maximum CP-violating asymmetries are more than 50% and 68% for \Lambda_b -> n \pi^+\pi^- and \Lambda_b -> \Lambda \pi^+\pi^-, respectively. With the aid of heavy quark symmetry and phenomenological models for the hadronic wave functions of \Lambda_b, \Lambda and the neutron, we estimate the branching ratios of \Lambda_b -> n (\Lambda)\rho^0. Comment: 20 pages, 2 figires, Latex
05/1998;
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