Analysis of the resonant components in (B)over-bar(0) -> J/psi pi(+)pi(-)

Interpretation of CP violation measurements using charmonium decays, in both the (B) over bar (0) and (B) over bar (0)(s) systems, can be subject to changes due to "penguin" type diagrams. These effects can be investigated using measurements of the Cabibbo-suppressed (B) over bar (0) -> J/psi pi(+)pi-decays. The final state composition of this channel is investigated using a 1.0 fb(-1) sample of data produced in 7 TeV pp collisions at the LHC and collected by the LHCb experiment. A modified Dalitz-plot analysis is performed using both the invariant mass spectra and the decay angular distributions. An improved measurement of the (B) over bar (0) -> J/psi pi(+)pi(-)branching fraction of (3.97 +/- 0.09 +/- 0.11 +/- 0.16) x 10(-5) is reported where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty of the branching fraction of the decay B- -> J/psi K- used as a normalization channel. Significant production of f(0)(500) and rho(770) resonances is found in the substructure of the J/psi pi(+)pi(-) final state, and this indicates that they are viable final states for CP violation studies. In contrast evidence for the f(0)(980) resonance is not found. This allows us to establish the first upper limit on the branching fraction product B((B) over bar (0) -> J/psi f(0)(980)) x B(f(0)(980) -> pi(+)pi(-)) < 1.1 x 10(-6), leading to an upper limit on the absolute value of the mixing angle of the f(0)(980) with the f(0)(500) of less than 31 degrees, both at 90% confidence level. DOI: 10.1103/PhysRevD.87.052001

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Concepts associés

Chargement

Publications associées

Chargement

Résumé

Official source

https://infoscience.epfl.ch/record/185306?ln=fr

À propos de ce résultat

Concepts associés (16)

Concepts associés

Chargement

Publications associées (124)

Publications associées

Chargement

LHCb

LHCb (Large Hadron Collider beauty experiment : Expérience du LHC sur le quark beauté) est une expérience de physique des particules utilisant les collisions de protons produites au collisionneur LHC

Rapport de branchement

En physique des particules et en physique nucléaire, le rapport de branchement (ou rapport d'embranchement) désigne la probabilité de voir un nucléide emprunter un mode de désintégration radioactive d

Radioactivité β

La radioactivité β, radioactivité bêta ou émission bêta (symbole β) est, à l'origine, un type de désintégration radioactive dans laquelle une particule bêta (un électron ou un positon) est émise. On

Analysis of the resonant components in (B)over-bar(s)(0) -> J/psi pi(+)pi(-)

Vladislav Balagura, Christophe Bauer, Aurelio Bay, Marc-Olivier Bettler, Frédéric Blanc, Joël Bressieux, Peter Clarke, Victor Coco, Greig Alan Cowan, Michel De Cian, Hans Dijkstra, Frédéric Guillaume Dupertuis, Vincent Fave, Christoph Frei, Neal Gauvin, Guido Haefeli, Plamen Hristov Hopchev, Pierre Jaton, Anne Keune, Mathias Oleg Knecht, Johan Luisier, Maurizio Martinelli, Raluca Anca Muresan, Bastien Luca Muster, Tatsuya Nakada, Matthew Needham, Niko Neufeld, Cédric Potterat, Jessica Prisciandaro, Albert Puig Navarro, Barinjaka Rakotomiaramanana, Gerhard Raven, Julien Rouvinet, Christophe Salzmann, Olivier Schneider, Frédéric Teubert, Mark Tobin, Minh Tâm Tran, Jian Wang, Yi Zhang, Lei Zhang

The decay (B) over bar (0)(s) -> J/psi pi(+)pi(-) can be exploited to study CP violation. A detailed understanding of its structure is imperative in order to optimize its usefulness. An analysis of this three-body final state is performed using a 1.0 fb(-1) sample of data produced in 7 TeV pp collisions at the LHC and collected by the LHCb experiment. A modified Dalitz plot analysis of the final state is performed using both the invariant mass spectra and the decay angular distributions. The pi(+)pi(-) system is shown to be dominantly in an S-wave state, and the CP-odd fraction in this (B) over bar (0)(s) decay is shown to be greater than 0.977 at 95% confidence level. In addition, we report the first measurement of the J/psi pi(+)pi(-) branching fraction relative to J/psi phi of (19.79 +/- 0.47 +/- 0.52)%.

Amer Physical Soc2012

Chargement

Amplitude Analysis of B-+/- -> pi(K+K-)-K-+/- Decays

Liupan An, Guido Andreassi, Vladislav Balagura, Aurelio Bay, Violaine Bellée, Federico Betti, Marc-Olivier Bettler, Frédéric Blanc, Maxim Borisyak, Chunhui Chen, Peter Clarke, Victor Coco, Tommaso Colombo, Greig Alan Cowan, Adam Davis, Michel De Cian, Hans Dijkstra, Mirco Dorigo, Paolo Durante, Dipanwita Dutta, François Fleuret, Christoph Frei, Olivier Göran Girard, Elena Graverini, Guido Haefeli, Xiaoxue Han, Plamen Hristov Hopchev, Thibaud Humair, Chitsanu Khurewathanakul, Veronica Sølund Kirsebom, Axel Kuonen, Yiming Li, Vladimir Macko, Pietro Marino, Maurizio Martinelli, Tatsuya Nakada, Tara Nanut, Matthew Needham, Niko Neufeld, Preema Rennee Pais, Luca Pescatore, Anton Petrov, Guillaume Max Pietrzyk, Jessica Prisciandaro, Renato Quagliani, Gerhard Raven, Federico Leo Redi, Olivier Schneider, Maxime Schubiger, Sebastian Schulte, Evgenii Shmanin, Pavol Stefko, Maria Elena Stramaglia, Liang Sun, Zhipeng Tang, Frédéric Teubert, Mark Tobin, Minh Tâm Tran, Maria Vieites Diaz, Mingkui Wang, Jian Wang, Zheng Wang, Yi Wang, Zhirui Xu, Hang Yin, Lei Zhang, Yi Zhang, Yu Zheng

The first amplitude analysis of the B-+/- -> pi(K+K-)-K-+/- decay is reported based on a data sample corresponding to an integrated luminosity of 3.0 fb(-1) of pp collisions recorded in 2011 and 2012 with the LHCb detector. The data are found to be best described by a coherent sum of five resonant structures plus a nonresonant component and a contribution from pi pi KK S-wave rescattering. The dominant contributions in the pi(+/-) K(-/+ )and K+ K- systems are the nonresonant and the B-+/- -> rho(1450)(0)pi(+/-) amplitudes, respectively, with fit fractions around 30%. For the rescattering contribution, a sizable fit fraction is observed. This component has the largest CP asymmetry reported to date for a single amplitude of (-66 +/- 4 +/- 2)%, where the first uncertainty is statistical and the second systematic. No significant CP violation is observed in the other contributions.

AMER PHYSICAL SOC2019

Chargement

The analog readout of the LHCb vertex detector and study of the measurement of the Bs oscillation frequency

Jérémie Borel

The LHCb detector is one of the four experimental setups built to detect high-energy proton collisions to be produced by the Large Hadron Collider (LHC). Located at CERN (Geneva, Switzerland), the LHC machine and the LHCb experiment are expected to start in 2008, and will then operate for several years. Being the largest collider of its kind, the LHC will open the way to new investigations, in the very-high energies, but also in terms of statistics for the study of rare-phenomena and flavor physics. In this framework LHCb is dedicated to precise measurements of CP-violating and rare decays of beauty hadrons, in order to test (or over-constrain) the Standard Model of particle physics. From the hardware point of view, the construction of such detectors represents several challenges; one of them is the routing at a very high frequency of many signals in a harsh radiation environment. We designed to this purpose a hardware setup and a software filter which together reduce the cross-talk present in the readout of the LHCb vertex detector to a level of (1 ± 2)%, leading to an improved signal quality in the acquisition chain. From the physics point of view, many of the CP-violation measurements performed at LHCb using Bs decays, for example using Bs → Ds∓ K± decays, will require as input the Bs–Bs oscillation frequency Δms. Thus the measurement of Bs–Bs oscillations, which are best observed using the flavor-specific Bs → Ds- π+ decays, will play an important role. We have developed a complete selection of Bs → Ds- π+ and Bs → Ds∓ K± events, based on Monte Carlo simulations. Assuming 2 fb-1 of data, we expect a Bs → Ds- π+ signal yield, after the first level of trigger, of 155 k events over a background between 0.6 k and 7.8 k events at 90% confidence level. Moreover, we assess with fast Monte Carlo studies the corresponding statistical sensitivity on the Bs oscillation frequency, σ(Δms) = 0.008 ps-1, on the wrong tag fraction, σ(ω) = 0.003, as well as on other parameters related to the Bs-meson system. We also addressed an important aspect of the systematics associated with the Δms measurement, and developed a method to calibrate and assess the length scale. This calibration is performed through the reconstruction of secondary interactions occurring in the material of the vertex detector. We show that the statistical relative precision of this approach quickly matches 6 × 10-5, obtained from the survey measurements of the detector.

EPFL2008

Chargement