# Evidence for $B^0 \to \rho^0\rho^0$ Decay and Implications for the CKM Angle $\alpha$

Abstract : We search for the decays B0->rho0rho0, B0->rho0f0, and B0->f0f0 in a sample of about 384 million Upsilon(4S)->BBbar decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We find evidence for B0->rho0rho0 with 3.5 sigma significance and measure the branching fraction BR = (1.07+-0.33+-0.19)10^-6 and longitudinal polarization fraction f_L = 0.87+-0.13+-0.04, where the first uncertainty is statistical, and the second is systematic. The uncertainty on the CKM unitarity angle alpha due to penguin contributions in B-> rho rho decays is 18 degrees at the 1 sigma level. We also set upper limits on the B0->rho0f0 and B0->f0f0 decay rates.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00120128
Contributor : Dominique Girod <>
Submitted on : Friday, January 5, 2007 - 1:12:22 PM
Last modification on : Thursday, June 17, 2021 - 3:46:23 AM

### Citation

B. Aubert, M. Bona, D. Boutigny, Y. Karyotakis, J.P. Lees, et al.. Evidence for $B^0 \to \rho^0\rho^0$ Decay and Implications for the CKM Angle $\alpha$. Physical Review Letters, American Physical Society, 2007, 98, pp.111801. ⟨10.1103/PhysRevLett.98.111801⟩. ⟨in2p3-00120128⟩

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