
Aiola, S., Bandiera, L., Cavoto, G., De Benedetti, F., Fu, J., Guidi, V., et al. (2021). Progress towards the first measurement of charm baryon dipole moments. Phys. Rev. D, 103(7), 072003–15pp.
Abstract: Electromagnetic dipole moments of shortlived particles are sensitive to physics within and beyond the Standard Model of particle physics but have not been accessible experimentally to date. To perform such measurements it has been proposed to exploit the spin precession of channeled particles in bent crystals at the LHC. Progress that enables the first measurement of charm baryon dipole moments is reported. In particular, the design and characterization on beam of silicon and germanium bent crystal prototypes, the optimization of the experimental setup, and advanced analysis techniques are discussed. Sensitivity studies show that first measurements of Lambda(+)(c) and Xi(+)(c) baryon dipole moments can he performed in two years of data taking with an experimental setup positioned upstream of the LHCb detector.



Antonelli, M. et al, MartinezVidal, F., & Pich, A. (2010). Flavor physics in the quark sector. Phys. Rep., 494(34), 197–414.
Abstract: In the past decade, one of the major challenges of particle physics has been to gain an indepth understanding of the role of quark flavor. In this time frame, measurements and the theoretical interpretation of their results have advanced tremendously. A much broader understanding of flavor particles has been achieved; apart from their masses and quantum numbers, there now exist detailed measurements of the characteristics of their interactions allowing stringent tests of Standard Model predictions. Among the most interesting phenomena of flavor physics is the violation of the CP symmetry that has been subtle and difficult to explore. In the past, observations of CP violation were confined to neutral K mesons, but since the early 1990s, a large number of CPviolating processes have been studied in detail in neutral B mesons. In parallel, measurements of the couplings of the heavy quarks and the dynamics for their decays in large samples of K, D, and B mesons have been greatly improved in accuracy and the results are being used as probes in the search for deviations from the Standard Model. In the near future, there will be a transition from the current to a new generation of experiments; thus a review of the status of quark flavor physics is timely. This report is the result of the work of physicists attending the 5th CKM workshop, hosted by the University of Rome “La Sapienza”, September 913, 2008. It summarizes the results of the current generation of experiments that are about to be completed and it confronts these results with the theoretical understanding of the field which has greatly improved in the past decade.



BABAR and Belle Collaborations(Abdesselam, A. et al), MartinezVidal, F., & Oyanguren, A. (2015). First Observation of CP Violation in (B)overbar(0) > D(CP)((*))h(0) Decays by a Combined TimeDependent Analysis of BABAR and Belle Data. Phys. Rev. Lett., 115(12), 121604–10pp.
Abstract: We report a measurement of the timedependent CP asymmetry of (B) over bar (0) > D(CP)((*))h(0) decays, where the light neutral hadron h(0) is a pi(0), eta , or omega meson, and the neutral D meson is reconstructed in the CP eigenstates K+K, KS(0)pi(0) or KS(0)omega. The measurement is performed combining the final data samples collected at the Upsilon(4S) resonance by the BABAR and Belle experiments at the asymmetricenergy B factories PEPII at SLAC and KEKB at KEK, respectively. The data samples contain (471 +/ 3) x 10(6) B (B) over bar pairs recorded by the BABAR detector and (772 +/ 11) x 10(6) B (B) over bar pairs recorded by the Belle detector. We measure the CP asymmetry parameters eta Sf = +0.66 +/ 0.10(stat) +/ 0.06(syst) and C = 0.02 +/ 0.07(stat) +/ 0.03(syst). These results correspond to the first observation of CP violation in (B) over bar (0) > D(CP)((*))h(0) decays. The hypothesis of no mixinginduced CP violation is excluded in these decays at the level of 5.4 standard deviations.



BABAR and Belle Collaborations(Adachi, I. et al), MartinezVidal, F., & Oyanguren, A. (2018). Measurement of cos 2 beta in B0 > D((*))h(0) with D > KS(0)pi(+) pi() decays by a combined timedependent Dalitz plot analysis of BABAR and Belle data. Phys. Rev. D, 98(11), 112012–29pp.
Abstract: We report measurements of sin 2 beta and cos 2 beta using a timedependent Dalitz plot analysis of B0 > D((*))h(0) with D > KS(0)pi(+)pi() decays, where the light unflavored and neutral hadron h(0) is a pi(0),eta, or omega meson. The analysis uses a combination of the final data sets of the BABAR and Belle experiments containing 471 x 10(6) and 772 x 10(6) B (B) over bar pairs collected at the gamma(4S) resonance at the asymmetricenergy B factories PEPII at SLAC and KEKB at KEK, respectively. We measure sin 2 beta = 0.80 +/ 0.14(stat) +/ 0.06(syst) +/ 0.03(model) and cos 2 beta = 0.91 +/ 0.22(stat) +/ 0.09(syst) +/ 0.07(model). The result for the direct measurement of the angle is beta = (22.5 +/ 4.4(stat) +/ 1.2(syst) +/ 0.6(model))degrees. The last quoted uncertainties are due to the composition of the D0 > KS(0)pi(+)pi() decay amplitude model, which is newly established by a Dalitz plot amplitude analysis of a highstatistics e(+) e() > c (c) over bar data sample as part of this analysis. We find the first evidence for cos 2 beta > 0 at the level of 3.7 standard deviations. The measurement excludes the trigonometric multifold solution pi/2 – beta = (68.1 +/ 0.7)degrees at the level of 7.3 standard deviations and therefore resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle. The hypothesis of beta = 0 degrees is ruled out at the level of 5.1 standard deviations, and thus CP violation is observed in B0 > D(*) h(0) decays. The measurement assumes no direct CP violation in B0 > D(*) h(0) decays.



BABAR and Belle Collaborations(Adachi, I. et al), MartinezVidal, F., & Oyanguren, A. (2018). First Evidence for cos 2 beta > 0 and Resolution of the CabibboKobayashiMaskawa QuarkMixing Unitarity Triangle Ambiguity. Phys. Rev. Lett., 121(26), 261801–11pp.
Abstract: We present first evidence that the cosine of the CPviolating weak phase 2 beta is positive, and hence exclude trigonometric multifold solutions of the CabibboKobayashiMaskawa (CKM) Unitarity Triangle using a timedependent Dalitz plot analysis of B0 > D(*) h(0) with D > KS(0)pi(+)pi() decays, where h(0) is an element of {pi(0), eta, omega} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the (sic)(4S) resonance at the asymmetricenergy B factories PEPII at SLAC and KEKB at KEK, respectively. The data samples contain (471 +/ 3) x 10(6) B (B) over bar pairs recorded by the BABAR detector and (772 +/ 11) x 10(6) B (B) over bar pairs recorded by the Belle detector. The results of the measurement are sin 2 beta = 0.80 +/ 0.14 (stat) +/ 0.06 (syst) +/ 0.03 (model) and cos 2 beta = 0.91 +/ 0.22(stat) +/ 0.09 (syst) +/ 0.07(model). The result for the direct measurement of the angle beta of the CKM Unitarity Triangle is beta = [22.5 +/ 4.4 (stat) +/ 1.2 (syst) +/ 0.6(model)]degrees. The measurement assumes no direct CP violation in B0 > D(*) h(0) decays. The quoted model uncertainties are due to the composition of the D0 > KS(0)pi(+)pi() decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a highstatistics e(+)e() > c (c) over bar data sample. CP violation is observed in B0 > D(*) h(0) decays at the level of 5.1 standard deviations. The significance for cos 2 beta > 0 is 3.7 standard deviations. The trigonometric multifold solution pi/2 – beta = (68.1 +/ 0.7)degrees is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.



BABAR Collaboration(Aubert, B. et al), Azzolini, V., LopezMarch, N., MartinezVidal, F., Milanes, D. A., & Oyanguren, A. (2013). The BABAR detector: Upgrades, operation and performance. Nucl. Instrum. Methods Phys. Res. A, 729, 615–701.
Abstract: The BABAR detector operated successfully at the PEPIl asymmetric e(+) e() collider at the SLAC National Accelerator Laboratory from 1999 to 2008. This report covers upgrades, operation, and performance of the collider and the detector systems, as well as the trigger, online and offline computing, and aspects of event reconstruction since the beginning of data taking.



BABAR Collaboration(Aubert, B. et al), Azzolini, V., LopezMarch, N., MartinezVidal, F., Milanes, D. A., & Oyanguren, A. (2010). Observation of the decay (B)overbar(0) > Lambda(+)(c)(p)overbar pi(0). Phys. Rev. D, 82(3), 031102–8pp.
Abstract: In a sample of 467 x 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP II collider at SLAC we have observed the decay (B) over bar (0) > Lambda(+)(c)(p) over bar pi(0) and measured the branching fraction to be (1.94 +/ 0.17 +/ 0.14 +/ 0.50 x 10(4), where the uncertainties are statistical, systematic, and the uncertainty on the Lambda(+)(c) > pK()pi(+) branching fraction, respectively. We determine an upper limit of 1.5 x 10(6) at 90% C.L. for the product branching fraction B((B) over bar (0) > Sigma(+)(c) (2455)(p) over bar) x B(Lambda(+)(c) > pK() pi(+)). Furthermore, we observe an enhancement at the threshold of the invariant mass of the baryon antibaryon pair.



BABAR Collaboration(Aubert, B. et al), Azzolini, V., LopezMarch, N., MartinezVidal, F., Milanes, D. A., & Oyanguren, A. (2010). Correlated leading baryonantibaryon production in e(+)e() > c(c)overbar > Lambda(+)(c)(Lambda)overbar(c)()X. Phys. Rev. D, 82(9), 091102–8pp.
Abstract: We present a study of 649 +/ 35 e(+)e() > c (c) over bar events produced at root s approximate to 10.6 GeV containing both Lambda(+)(c) baryon and a (Lambda) over bar ()(c) antibaryon. The number observed is roughly 4 times that expected if the leading charmed hadron types are uncorrelated, confirming an observation by the CLEO Collaboration. We find a 2jet topology in these events but very few additional baryons, demonstrating that the primary c and (c) over bar are predominantly contained in a correlated baryonantibaryon system. In addition to the charmed baryons we observe on average 2.6 +/ 0.2 charged intermediate mesons, predominantly pions, carrying 65% of the remaining energy.



BABAR Collaboration(Aubert, B. et al), Azzolini, V., LopezMarch, N., MartinezVidal, F., Milanes, D. A., & Oyanguren, A. (2010). Observation of the chi(c2)(2P) meson in the reaction gamma gamma > D(D)overbar at BABAR. Phys. Rev. D, 81(9), 092003–16pp.
Abstract: A search for the Z(3930) resonance in gamma gamma production of the D (D) over bar system has been performed using a data sample corresponding to an integrated luminosity of 384 fb(1) recorded by the BABAR experiment at the PEPII asymmetricenergy electronpositron collider. The D (D) over bar invariant mass distribution shows clear evidence of the Z(3930) state with a significance of 5.8 sigma. We determine mass and width values of (3926.7 +/ 2.7 +/ 1.1) MeV/c(2) and (21.3 +/ 6.8 +/ 3.6) MeV, respectively. A decay angular analysis provides evidence that the Z(3930) is a tensor state with positive parity and C parity (J(PC) = 2(++)); therefore we identify the Z(3930) state as the chi(c2)(2P) meson. The value of the partial width Gamma(gamma gamma) x B(Z(3930) > D (D) over bar) is found to be (0.24 +/ 0.05 +/ 0.04) keV.



BABAR Collaboration(Aubert, B. et al), Azzolini, V., LopezMarch, N., MartinezVidal, F., Milanes, D. A., & Oyanguren, A. (2010). Search for B+ > l(+)nu(l) recoiling against B > D(0)l()(nu)overbarX. Phys. Rev. D, 81(5), 051101–9pp.
Abstract: We present a search for the decay B+ > l(+)nu(l) (l = tau, mu, or e) in (458.9 +/ 5.1) x 10(6) B (B) over bar pairs recorded with the BABAR detector at the PEPII Bfactory. We search for these B decays in a sample of B+B events where one B meson is reconstructed as B > D(0)l()(nu) over barX. Using the method of Feldman and Cousins, we obtain B(B+ > tau(+)nu(tau)) = (1.7 +/ 0.8 +/ 0.2) x 10(4), which excludes zero at 2.3 sigma. We interpret the central value in the context of the standard model and find the B meson decay constant to be f(B)(2) = (62 +/ 31) x 10(3) MeV2. We find no evidence for B+ > e(+)nu(e) and B+ > mu(+)nu(mu) and set upper limits at the 90% C. L. B(B+ > e(+)nu(e)) < 0.8 x 10(5) and B(B+ > mu(+)nu(mu)) < 1.1 x 10(5).

