Measurements of gamma/phi_3 at B factories

Measurement of the CKM angle alpha with the B-factories

B-meson decays involving b->u transitions are sensitive to the Unitarity Triangle angle alpha (or phi_2). The B-factories at SLAC and KEK have made significant progress toward the measurement of alpha in recent years. This paper summarizes the results of the B-factories' constraints on alpha.

2005-12-20hep-ex

Radiative Penguin B Decays at the B Factories

In this article, I review the most recent results in radiative penguin decays from the B factories Belle and Babar. Most notably, I will talk about the recent new observations in the decays B -> (rho/omega) gamma, a new analysis technique in b -> s gamma, and first measurements of radiative penguin decays in the B_s meson system. Finally, I will summarize the current status and future prospects of radiative penguin B physics at the B factories.

2007-10-26hep-ex

Measurements of the CKM angle phi_3/gamma

We present a review on the measurements of the CKM angle gamma (phi_3) as performed by the BABAR and Belle experiments at the asymmetric-energy e+e- B factories colliders PEP-II and KEKB.

2007-06-19hep-ex

phi1/beta from B -> charmonium/charm modes

The asymmetric B-factories have provided valuable information on CP violation so far. In particular, one of the angles of the Unitarity Triangle, phi1(=beta), has been measured by several approaches. Since FPCP2004, some measurements have been updated and improved. In this letter, the latest status of phi1 measurements, performed at BaBar and Belle experiments usgin B -> charm/charmonium decays, are reported.

2006-05-16hep-ex

The radiative return at phi- and B-factories: small-angle photon emission at next to leading order

The radiative return offers the unique possibility for a measurement of the cross section of electron--positron annihilation into hadrons over a wide range of energies. The large luminosity of present phi- and B-factories easily compensates for the additional factor of alpha due to the emission of a hard photon. Final states with photons at large angles can be easily identified. The rate for events with collinear photons, however, is enhanced by a large logarithm and allows, in particular at lower energies, for a complementary measurement. The Monte Carlo generator PHOKHARA, which includes nex…

2005-01-27hep-exhep-ph

The radiative return at phi- and B-factories: FSR at next-to-leading order

The measurement of the pion form factor and, more generally, of the cross section for electron--positron annihilation into hadrons through the radiative return has become an important task for high luminosity colliders such as the $Φ$- or $B$-meson factories. For detailed understanding and analysis of this reaction, the construction of a Monte Carlo program, PHOKHARA, has been undertaken. Version 2.0 was based on a next-to-leading order (NLO) treatment of the corrections from initial-state radiation (ISR). In the present paper a further extension of PHOKHARA (version 3.0) is described, which i…

2004-01-08hep-exhep-ph

Evidence of phi --> pi0 pi0 gamma and phi --> pi0 eta gamma decays in SND experiment at VEPP-2M

Preliminary results on the study of e+e- --> phi(1020) --> pi0 pi0 gamma, eta pi0 gamma processes from SND experiment at VEPP-2M collider in Novosibirsk are presented. Branching ratios of rare radiative phi --> pi0 pi0 gamma and phi --> pi0 eta gamma decays are measured: B(phi --> pi0 pi0 gamma ) = (1.1 +- 0.2) * 10^-4 (invariant mass (pi0 pi0) < 800 MeV), B(phi --> eta pi0 gamma ) = (1.3 +- 0.5) * 10^-4.

1997-11-27hep-ex

Study of the Decay phi --> eta pi0 gamma with the KLOE detector

In a sample of 5.3x10^7 phi-decays observed with the KLOE detector at the Frascati phi-factory Dafne we find 605 eta pi0 gamma events with eta --> gammaγand 197 eta pi0 gamma events with eta --> pi+ pi- pi0. The decay phi --> eta pi0 gamma is dominated by the process phi --> a0 gamma. From a fit to the eta pi0 mass spectrum we find BR(phi --> ao(980) gamma)= (7.4 +- 0.7)x10^-5.

2002-04-23hep-ex

Measurements of gamma/ phi3

This report summarizes the progress in measuring the angle gamma (or phi3) of the Unitarity Triangle.

2009-05-08hep-ex

Search for rare Phi decays in pi+ pi_ gamma final state

A search for phi radiative decays has been performed using a data sample of about 2.0 million phi decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. From the selected e+ e- -> pi+ pi- gamma events the following results were obtained: B(phi -> f0(980) gamma) < 1x10-4 for destructive and B(phi -> f0(980) gamma) < 7x10-4 for constructive interference with the Bremsstrahlung process respectively, B(phi -> gamma -> pi+ pi- gamma) < 3x10-5 for E of gamma > 20 MeV, B(phi -> rho gamma) < 7x10-4. From the selected e+ e- -> mu+ mu- gamma events B(phi -> mu+ mu- gamma) = (2.3+-1.0…

1997-11-14hep-ex

Observation of B_s to phi gamma and Search for B_s to gamma gamma Decays at Belle

We search for the radiative penguin decays B_s to phi gamma and B_s to gamma gamma in a 23.6 fb-1 data sample collected at the Upsilon(5S) resonance with the Belle detector at the KEKB e+e- asymmetric-energy collider. We observe for the first time a radiative penguin decay of the B_s meson in the B_s to phi gamma mode. No significant B_s to gamma gamma signal is observed.

2008-02-26hep-ex

Measurement of B Decays to phi K gamma

We search for the decays B- -> phi K- gamma and B0bar -> phi K0bar gamma in a data sample of 228 million BBbar pairs collected at the Upsilon(4S) resonance with the BaBar detector. We measure the branching fraction B(B- -> phi K- gamma) = (3.5 +/- 0.6 +/- 0.4) x 10^-6 and set an upper limit B(B0bar -> phi K0bar gamma) < 2.7 x 10^-6 at the 90% confidence level. We also measure the direct CP asymmetry in B- -> phi K- gamma, A_CP = (-26 +/- 14 +/- 5)%. The uncertainties are statistical and systematic, respectively.

2006-11-21hep-ex

Study of the Decay phi --> pi0 pi0 gamma with the KLOE Detector

We have measured the branching ratio BR(phi --> pi0 pi0 gamma) with the KLOE detector using a sample of ~5x10^7 phi decays. phi mesons are produced at DAFNE, the Frascati phi-factory. We find BR(phi --> pi0 pi0 gamma) = (1.09 +- 0.03 (stat) +- 0.05 (syst))x10^-4. We fit the two--pion mass spectrum to models to disentangle contributions from various sources.

2002-04-24hep-ex

Study of the radiative decay phi to a0(980) gamma with the KLOE detector

A sample of 1.25x10^9 phi decays, collected with the KLOE detector at the Frascati phi-factory DAFNE at center of mass energy ~ Mphi, has been used to study the radiative decay phi to eta pi0 gamma. This decay is dominated by phi to a0(980) gamma. Two decay chains, corresponding to eta to gamma gamma and eta to pi+ pi- pi0, have been selected. We found respectively: Br(phi to eta pi0 gamma)=(6.92 +/- 0.10 (stat.) +/- 0.20 (syst.))x10^(-5) and (7.19 +/- 0.17 (stat.) +/- 0.24 (syst.))x 10 ^(-5). The eta pi0 invariant mass distributions have been fitted to obtain the relevant a0(980) parameters.

2007-07-31hep-ex

Belle time-integrated phi3 (gamma) measurements

We report recent results by the Belle collaboration on the determination of the CP-violating angle phi3 (gamma) using time-integrated methods.

2011-01-05hep-ex

Measurement of the CKM angle gamma (phi3) using B->DK decays

We present the status of the measurement of the CKM CP-violating phase gamma (phi3) performed using B->D(*)K(*) decays. We review and compare the main experimental results.

2010-01-16hep-ex

Charm Input for Determining gamma/phi_3

Overconstraining the CKM unitarity triangle with precision measurements of its angles continues to test the validity of the Standard Model. One of these angles, gamma/phi_3, has been measured by studying B+- -> D K+- decays, where D = D0 or D0-bar. I present recent results of hadronic D decays which will improve the sensitivity of gamma/phi_3 measurements.

2009-08-23hep-ex

Search for the Radiative Decay B --> phi gamma

We perform a search for the exclusive radiative decay B0 --> phi gamma, which is dominated by b d annihilation, in a sample of 124 million BB events collected with the BABAR detector at the PEP-II asymmetric-energy e+e- storage ring at SLAC. No significant signal is seen. We set an upper limit on the branching fraction BR(B0 --> phi gamma < 8.5x10-7) at the 90% confidence level.

2005-11-24hep-ex

Measurement of B Decays to phi K gamma

We measure the branching fraction of the radiative B- decay B(B- -> phi K- gamma) = (3.46 +/- 0.57^{+0.39}_{-0.37}) 10^-6, and set an upper limit on the radiative B0 decay B(B0 -> phi K0 gamma) < 2.71 10^-6 at 90% confidence level. We also measure the direct CP asymmetry of the B- -> phi K- gamma mode A_CP = (-26.4 +/- 14.3 +/- 4.8)%. The uncertainties are statistical and systematic, respectively. These measurements are based on 207 1/fb of data collected at the Y4S resonance with the BABAR detector.

2006-07-20hep-ex

Observation of the phi to eta' gamma decay with four charged particles and photons in the final state

Using 11.6 1/pb of data collected in the energy range 0.864-1.06 GeV by CMD-2 at VEPP-2M, the rare decay mode phi to eta' gamma was observed via the decay chain eta' to pi+pi- eta, eta to pi+pi-pi0 or eta to pi+pi- gamma. The following branching ratio was obtained: Br(phi to eta' gamma) = (4.9^{+2.2}_{-1.8} +- 0.6) \cdot 10^{-5}.

2000-10-09hep-ex

Radiative Penguin Decays of B Mesons: Measurements of B -> K* gamma, B -> K2*(1430) gamma, and Search for B0 -> phi gamma

Electromagnetic radiative penguin decays of the B meson were studied with the BaBar detector at SLAC's PEP-II asymmetric-energy B Factory. Branching fractions and isospin asymmetry of the decay B -> K* gamma, branching fractions of B -> K2*(1430) gamma, and a search for B0 -> phi gamma are presented. The decay rates may be enhanced by contributions from non-standard model processes.

2004-12-23hep-ex

Measurements of quantum-correlated D0D0bar decays related to the determination of gamma/phi3

Quantum-correlated measurements of D0D0bar decays related to the determination of the Unitarity Triangle angle gamma/phi3 are reviewed. Measurements from the CLEO Collaboration are presented and prospects with the BES III experiment are discussed.

2012-12-19hep-ex

Quantum-correlated measurements related to the determination of gamma/phi3

Measurements of D0 meson strong-phase parameters in quantum-correlated psi(3770) -> D0 D0bar decays by the CLEO collaboration are presented. These measurements play an important role in the determination of the unitarity triangle angle gamma/phi3 from B-meson decays. Measurements of the strong-phase parameters for D0->K0 pi+ pi-, D0 -> K0 K+ K-, D0 -> K- pi+ pi0, and D0 -> K- pi+ pi+ pi- decays are described along with their impact on the determination of gamma/phi3.

2010-12-13hep-ex

Ultimate sensitivity on gamma/phi3 from B->DK

Measurement of the CKM phase gamma in B->DK decays can be potentially performed with high precision due to low theoretical uncertainties. However, the precision measurement requires very large experimental samples of B decays. This report covers prospects for gamma measurement at the future e+e- facilities and upgraded LHCb detector.

2011-01-24hep-ex

Time-dependent angular analysis of the decay Bs -> J/psi phi and extraction of Delta Gamma_s and the CP-violating weak phase phi_s by ATLAS

A measurement of Bs J/psi phi decay parameters, including the CP-violating weak phase phi_s and the decay width difference Delta Gamma_s is reported, using 4.9 fb-1 of integrated luminosity collected in 2011 by the ATLAS detector from LHC pp collisions at a centre- of-mass energy sqrt(s) = 7 TeV. The mean decay width Gamma_s and the transversity amplitudes |A0(0)|^2 and |A||(0)|^2 are also measured. The values reported for these parameters are: phi_s = 0.22 \pm 0.41 (stat.) \pm 0.10 (syst.) rad Delta Gamma_s = 0.053 \pm 0.021 (stat.) \pm 0.010 (syst.) ps-1 Gamma_s = 0.677 \pm 0.007 (stat.) \pm…

2013-03-24hep-ex

Search for phi to K0 K0bar gamma decay with KLOE

The KLOE collaboration has searched for the phi to K0 K0bar gamma decay using a sample of 1.4 fb-1 of e+e- collisions at W ~ M(phi) collected with the KLOE experiment at the Frascati e+e- collider DAFNE. No previous search exists for this decay, while many theory models predict a BR of 10-8 for this channel. We set a preliminary value of the U.L. on this BR to 1.8x10-8 at 90% C.L.. This limit rules out most of the existing theory predictions.

2007-07-31hep-ex

Measurement of the CP-violating weak phase phi[s] and the decay width difference Delta Gamma[s] using the Bs to J/Psi phi(1020) decay channel in pp collisions at sqrt(s) = 8 TeV

The CP-violating weak phase phi[s] of the Bs meson and the decay width difference Delta Gamma[s] of the Bs light and heavy mass eigenstates are measured with the CMS detector at the LHC using a data sample of Bs to J/Psi phi(1020) to mu+mu-K+K- decays. The analysed data set corresponds to an integrated luminosity of 19.7 inverse femtobarns collected in pp collisions at a centre-of-mass energy of 8 TeV. A total of 49,200 reconstructed Bs decays are used to extract the values of phi[s] and Delta Gamma[s] by performing a time-dependent and flavour-tagged angular analysis of the mu+mu-K+K- final s…

2016-04-19hep-ex

Measurement of Gamma(phi -> eta' gamma)/Gamma(phi -> eta gamma) and the pseudoscalar mixing angle

We have measured the radiative decays phi -> eta gamma, phi ->etaprime gamma selecting pi+ pi- gamma gamma gamma final state in a sample of about 5 times 10^7 phi mesons produced at the Frascati phi factory DAFNE. We obtain Gamma(phi -> etaprime gamma)/Gamma(phi -> eta gamma)=(4.70 +- 0.47 +- 0.31) times 10^-3. From this result we derive new accurate values for the branching ratio BR(phi ->etaprime gamma) = (6.10 +- 0.61 +- 0.43) times 10^-5, and the mixing angle of pseudoscalar mesons in the flavour basis phi_P=(41.8 +1.9 -1.6) degrees.

2002-06-05hep-exhep-ph

Time-integrated measurements of the CKM angle gamma/phi3 in BABAR

The most recent determinations of the CKM angle gamma/phi3 by the BABAR Collaboration, using time-integrated observables measured in charged B --> D(*)K(*) decays, are presented.The measurements have been performed on the full sample of 468 million BBbar pairs collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B factory in the years 1999-2007.

2010-12-22hep-ex

Dalitz plot analysis of e+ e- --> pi0 pi0 gamma events at SQRT(s) ~ M(phi) with the KLOE detector

We have studied the Dalitz plot of the e+ e- --> pi0 pi0 gamma events collected at SQRT(s) ~ M(phi) with the KLOE detector. In the dipion invariant mass (Mpp) region below 700 MeV, the process under study is dominated by the non-resonant process e+ e- --> omega pi0 with omega --> pi0 gamma whereas, for higher Mpp values, the radiative phi decay to the f0(980) is the dominant mechanism. Different theoretical models are used to fit the Dalitz plot, taking also into account a possible contribution of the sigma(600). For each model, we extract the f0(980) mass and its coupling to pipi, KKbar and t…

2006-09-06hep-ex

Experimental study of the decay PHI(1020)--->ETA+GAMMA in multi-photon final state

In the SND experiment at VEPP-2M e^+e^- collider the phi(1020) ---> eta+gamma ---> 3pi^0+gamma decay was studied. The branching ratio B(phi--->eta+gamma) = (1.246 +- 0.025 +- 0.057)% was measured.

1998-09-02hep-ex

Experimental Prospects for B -> X(s/d)gamma and B -> X(s)l+l-

In this report, experimental prospects for the inclusive analysis of the radiative B decays and electroweak penguin decays at the super B factories are presented.

2011-02-05hep-ex

Evidence of the PHI(1020)--->ETA+PI0+GAMMA Decay

Signal of the rare radiative decay PHI--->ETA+PI0+GAMMA was observed in the SND experiment at VEPP-2M electron-positron collider.The result is based on the analysis of data, corresponding to a total integrated luminosity of 4 pb^{-1}, or 8x10^6 PHI mesons produced. The measured branching ratio of PHI--->ETA+PI0+GAMMA decay is equal to (0.83+-0.23)x10^{-4}.

1998-09-12hep-ex

First Observation of PHI(1020)--->PI0+PI0+GAMMA Decay

In the SND experiment at the VEPP-2M electron-positron collider the PHI(1020)--->PI0+PI0+GAMMA decay was studied. The branching ratio B(PHI--->PI0+PI0+GAMMA)=(1.14+-0.10+-0.12)x10^{-4} was measured. It was shown, that the F0(980)GAMMA mechanism dominates in this decay and the 4-quark model of F0(980) describes our data most consistently.

1998-10-09hep-ex

Light Meson Spectroscopy with the Kloe Experiment

We describe the status of the analyses in progress on light meson spectroscopy in the KLOE experiment. We present the analyses of phi decays into f0(980)gamma and a0(980)gamma, the Dalitz plot analysis of the eta to pie+ pie- pie0 decay, the branching ratio measurement of eta to pie0 gamma gamma, the upper limits on Br(eta to 3 gamma) and Br(eta to pie^+ pie^-), the measurement of the ratio Br(phi to eta' gamma)/Br(phi to eta gamma) and phi leptonic width measurements.

2004-10-25hep-ex

Recent Results from the KLOE Experiment at DAPHNE

Recent results from the KLOE experiment at the DAPHNE e+e- collider are presented. KLOE has collected about 500 pb^-1 of data in the years from 2000 to 2002. Preliminary results are obtained using wide samples of the full statistics and include: the BR of the Ke3 decay of the K_S and the first measurement of its charge asymmetry, the ratio BR(K_S-->pi+pi-(gamma))/BR(K_S-->pi^0pi^0), the ratio BR(K_L-->gammagamma)/BR(K_L-->3pi^0), a detailed study of the decay phi-->pi+pi-pi^0, the ratio BR(phi-->eta' gamma)/BR(phi-->eta gamma) and the pseudoscalar mixing angle phi_P, the phi-->f_0 gamma and th…

2003-05-30hep-ex

Higher-order corrections to exclusive production of charmonia at B factories

As a test of the color-singlet mechanism of the nonrelativistic QCD (NRQCD) factorization approach, we consider the exclusive two-quarkonium productions in electron-positron annihilation e+ e- -> eta_c + gamma and e+ e- -> J/psi + J/psi at B factories. The cross sections are computed to the next-to-leading order in alpha_s and are resummed to all orders in half the relative velocity v of the charm quark in each meson rest frame. The available theoretical prediction of the cross section for e+ e- -> J/psi + eta_c at the same level of theoretical accuracies is consistent with the available exper…

2012-09-10hep-exhep-ph

Search for the decay phi -> K0 K0bar gamma with the KLOE experiment

We have searched for the decay phi -> K0 K0bar gamma, by detecting K_s pairs plus a photon and with the K_s-mesons decaying to pi^+ pi^-, in a sample of about 1.5x 10^9 phi-decays collected by the KLOE experiment at DAFNE. The reaction proceeds through the intermediate states f_0(980) gamma, a_0(980) gamma. We find five events with 3.2 events expected from background processes. We obtain the upper limit: BR (phi -> K0 K0bar gamma) < 1.9x10^-8 at 90% C.L. .

2009-06-17hep-ex

First model-independent determination of the relative strong phase between D0 and D0B --> K0Spi+pi- and its impact on the CKM Angle gamma/phi3 measurement

We exploit the quantum coherence between pair-produced D0 and D0B in psi(3770) decays to make a first determination of the relative strong phase differences between D0--> K0Spi+pi- and D0B--> K0Spi+pi-, which are of great importance in determining the CKM angle gamma/phi3 in B- --> D0 (D0B) K- decays. Using 818 1/pb of e+e- collision data collected with the CLEO-c detector at Ecm = 3.77 GeV, we employ a binned Dalitz-plot analysis of K0S pi+pi- and K0Lpi+pi- decays recoiling against flavor-tagged, CP-tagged and K0Spi+pi- tagged events to determine these strong phase differences.

2009-03-10hep-ex

Study of the a_0(980) meson via the radiative decay phi->eta pi^0 gamma with the KLOE detector

We have studied the phi->a_0(980) gamma process with the KLOE detector at the Frascati phi-factory DAPhNE by detecting the phi->eta pi^0 gamma decays in the final states with eta->gamma gamma and eta->pi^+ pi^- pi^0. We have measured the branching ratios for both final states: Br(phi->eta pi^0 gamma)=(7.01 +/- 0.10 +/- 0.20)x10^-5 and (7.12 +/- 0.13 +/- 0.22)x10^-5 respectively. We have also extracted the a_0(980) mass and its couplings to eta pi^0, K^+ K^-, and to the phi meson from the fit of the eta pi^0 invariant mass distributions using different phenomenological models.

2009-04-21hep-ex

A Study of J/psi-->gamma gamma V(rho,phi) Decays with the BESII Detector

Using a sample of $58\times 10^6$ $J/ψ$ events collected with the BESII detector, radiative decays $J/ψ\toγγV$, where $V=ρ$ or $ϕ$, are studied. A resonance around 1420 MeV/c$^2$ (X(1424)) is observed in the $γρ$ mass spectrum. Its mass and width are measured to be $1424\pm 10(stat)\pm 11(sys)$ MeV/c$^2$ and $ 101.0\pm 8.8 \pm 8.8$ MeV/c$^2$, respectively, and its branching ratio $B(J/ψ\to γX(1424)\to γγρ)$ is determined to be $(1.07\pm0.17 \pm 0.11)\times 10^{-4}$. A search for $X(1424)\to γϕ$ yields a 95% C.L. upper limit $B(J/ψ\to γX(1424)\to γγϕ) < 0.82 \times 10^{-4}$.

2004-04-26hep-ex

Prospects for measuring gamma at BaBar

The prospects for measuring the angle gamma with present day B factories are examined. A number of approaches are discussed with reference to recent preliminary measurements based on a data sample of approximately 88 million \BB pairs collected by the BaBar detector at the PEP-II asymmetric B Factory at SLAC.

2003-07-15hep-ex

Measurement of the ratio Gamma(K_L -> gamma gamma)/Gamma(K_L -> pi^0 pi^0 pi^0) with the KLOE detector

We have measured the ratio R=Gamma(K_L -> gamma gamma)/ Γ(K_L -> 3 pi^0) using the KLOE detector. From a sample of ~ 10^9 phi-mesons produced at DAFNE, the Frascati phi-factory, we select ~ 1.6 10^8 K_L-mesons tagged by observing K_S -> pi^+ pi^- following the reaction e^+ e^- -> phi -> K_L K_S. From this sample we select 27,375 K_L -> gamma gamma events and obtain R = (2.79 \pm 0.02_{stat} \pm 0.02_{syst}) \times 10^{-3}. Using the world average value for BR(K_{L} -> 3 pi^0), we obtain BR(K_{L} -> gamma gamma) = (5.89 \pm 0.07 \pm 0.08) \times 10^{-4} where the second error is due to the unce…

2003-05-15hep-ex

Upper Limit on the eta to gamma gamma gamma Branching Ratio with the KLOE Detector

We have searched for the C-violating decay eta to gamma gamma gamma in a sample of ~ 18 million eta mesons produced in phi to eta gamma decays, collected with the KLOE detector at the Frascati phi-factory DAFNE. No signal is observed and we obtain the upper limit BR(eta to gamma gamma gamma) less equal than 1.6x10^(-5) at 90 % C.L.

2004-06-08hep-ex

Measurement of Lifetime and Decay-Width Difference in B0s -> J/psi phi Decays

We measure the mean lifetime, tau=2/(Gamma_L+Gamma_H), and the width difference, DeltaGamma=Gamma_L-Gamma_H, of the light and heavy mass eigenstates of the B0s meson, B0sL and B0sH, in B0s -> J/psi phi decays using 1.7 fb^-1 of data collected with the CDF II detector at the Fermilab Tevatron ppbar collider. Assuming CP conservation, a good approximation for the B0s system in the Standard Model, we obtain DeltaGamma = 0.076^+0.059_-0.063 (stat.) +- 0.006 (syst.) ps^-1 and tau = 1.52 +- 0.04 (stat.) +- 0.02 (syst.) ps, the most precise measurements to date. Our constraints on the weak phase and …

2008-04-01hep-ex

Analysis of nature of phi -> gamma pi0 eta and phi -> gamma pi0 pi0 decays

We study interference patterns in the phi -> gamma a0 + pi0 rho -> gamma pi eta and phi -> gamma f0 + pi0 rho -> gamma pi0 pi0 reactions. Taking into account the interference, we fit the experimental data and show that the background reaction does not distort the pi0eta spectrum in the decay phi -> gamma pi eta everywhere over the energy region and does not distort the pi0 pi0 spectrum in the decay phi -> gamma pi0 pi0 when the invariant mass m_{pi0 pi0} > 670 MeV. We discuss the details of the scalar meson production in the radiative decays and note that there are conclusive arguments in favo…

2001-10-04hep-exhep-phnucl-th

eta Physics and phi Radiative Decays at Kloe

Here we present KLOE results on the phi meson decays in pi0 pi0 gamma, pi+ pi- gamma and eta pi0 gamma, the measurement of the ratio Br(phi to eta' gamma)/Br(phi to eta gamma) with the estimate of the eta' gluonium content and the measurement of the eta mass.

2007-05-24hep-ex

Observation of radiative B -> phi K gamma decays

The radiative decay $B \to ϕK γ$ is observed for the first time. The branching fraction for the charged $B^- \to ϕK^- γ$ decay mode is measured to be ${\cal B}(B^- \to ϕK^- γ) = (3.4 \pm 0.9 \pm 0.4) \times 10^{-6}$. The photon energy distribution for the $B^- \to ϕK^- γ$ decay is presented. The signal for the neutral $\bar{B}^0 \to ϕ\bar{K}^0 γ$ decay mode is not statistically significant and an upper limit, ${\cal B}(\bar{B}^0 \to ϕ\bar{K}^0 γ) < 8.3 \times 10^{-6}$ at $90% {\rm CL}$, is set. The analysis is based on a dataset of 90 fb$^{-1}$ collected by the Belle experiment at the $e^+ e^-…

2003-09-01hep-ex

First Physical Results from SND Detector at VEPP-2M

The paper describes experiments with the SND detector at VEPP-2M collider, carried out during the period from October 1995 until June 1997. The total integrated luminosity of 6.4 pb^{-1} was collected in the energy range 2E=0.4-1.4 GeV (MHAD97 experiment), corresponding to 4*10^5 mu^+ mu^- pairs produced. Preliminary results of the 1996 phi-meson experiment (FI96) are presented. The total number of phi-mesons produced is 4*10^6. New data on rare decays of phi and eta (550) mesons, in particular B(phi -> eta gamma) = (1.30+-0.06+-0.07)%, B(phi -> pi^0 pi^0 gamma) = (1.1+-0.2)*10^{-4}, (M_{pi^0 …

1997-10-22hep-ex

CP Violation with Bs -> J/Psi phi at the Tevatron

Recent results using B_s -> J/Psi phi decays for measuring the CP violating phase, phi_s, and the decay width difference for the two mass eigenstates, Delta Gamma_s, are presented from the CDF and D0 experiments at the Fermilab Tevatron collider.

2011-07-01hep-ex

Study of the Processes e+ e- --> eta gamma, e+ e- --> pi0 gamma --> 3 gamma in the c.m. Energy Range 600--1380 MeV at CMD-2

The processes e+ e- --> eta gamma, e+ e- --> pi0 gamma --> 3 gamma have been studied in the c.m. energy range 600--1380 MeV with the CMD-2 detector. The following branching ratios have been determined: Br(rho --> eta gamma) = (3.21 +- 1.39 +- 0.20)x 10^{-4}; Br(omega --> eta gamma) = (4.44 + 2.29 -1.83 +- 0.28)x 10^{-4}; Br(phi --> eta gamma) = (1.373 +- 0.014 +- 0.085)x 10^{-2}; Br(rho --> pi0 gamma) = (6.21 +1.28 - 1.18 +- 0.39)x 10^{-4}; Br(omega --> pi0 gamma) = (9.06 +- 0.20 +- 0.57)x 10^{-2}; Br(phi --> pi0 gamma) = (1.258 +- 0.037 +- 0.077)x 10^{-3};

2004-11-08hep-ex

Improving the precision of gamma/phi_3 via CLEO-c Measurements

Quantum correlations in $ψ(3770) \to D^0\bar{D}^0$ provide unique access to information about strong phase differences. Precision determination of the CKM phase $γ/ϕ_3$ via $B \to D K$ decays depends upon constraints on charm mixing amplitudes, measurements of doubly-Cabibbo suppressed amplitudes and relative phases, and studies of correlated charmed meson decays tagged by flavor or CP eigenstates. CP-tagged $D^0 \to K^-π^+π^-π^+$ decays and CP-tagged $D^0 \to K^0_Sπ^+π^-$ Dalitz plots are only available at CLEO-c. Using the 818 pb$^{-1}$ CLEO-c data sample produced by the Cornell Electron Sto…

2008-10-20hep-ex

Measurement of the Absolute Branching Ratio for the K+ -> mu+ nu(gamma) Decay with the KLOE Detector

We have measured the fully inclusive K+ -> mu+nu(gamma) absolute branching ratio with the KLOE experiment at DAFNE, the Frascati Phi-factory. From some 865,283 K+ -> mu+nu(gamma) decays obtained from a sample of about 5.2x10^8 Phi-meson decays, we find BR(K+ -> mu+ nu (gamma)) = 0.6366 +-0.0009(stat.) +-0.0015(syst.), corresponding to an overall fractional error of 0.27%. Using recent lattice results on the decay constants of pseudoscalar mesons one can obtain an estimate for the CKM mixing matrix element |Vus|=0.2223+-0.0026.

2005-10-12hep-ex

Clean Signals of CP-violating and CP-conserving New Physics in B->P V gamma Decays at B Factories and Hadron Colliders

In radiative B decays to final states containing one spin zero meson, one spin one meson and a photon, the photon polarization can be measured from the angular distribution of the final state. The P-odd, C-even components of this distribution lead to triple correlation asymmetries that are very sensitive to new physics as they are likely to receive only tiny contributions from the Standard Model. There are also (CP-conserving) forward-backward asymmetries to which there may be SM contributions of a few percent; nevertheless there is a data driven means to overcome the SM ``pollution''. These l…

2007-01-04hep-exhep-ph