The KEDR detector Anashin, V. V.; Aulchenko, V. M.; Baldin, E. M. ...
Physics of particles and nuclei,
07/2013, Letnik:
44, Številka:
4
Journal Article
Recenzirano
The KEDR detector is a universal magnetic detector designed for studying the
c
- and
b
-quarks and two-photon physics, and is employed at the VEPP-4M
e
+
e
−
collider. A specific feature of the ...experiment is the measurement of absolute beam energy using two methods: the resonant depolarization and the faster but less precise Compton backscattering of laser photons. This allowed a large series of measurements to be performed, in which the accuracy of determination of such fundamental parameters of particles as mass and total and leptonic widths was improved.
Based on the full BABAR data sample of 466.5 million BB¯ pairs, we present measurements of the electron spectrum from semileptonic B meson decays. We fit the inclusive electron spectrum to ...distinguish Cabibbo-Kobayashi-Maskawa (CKM) suppressed B→Xueν decays from the CKM-favored B→Xceν decays, and from various other backgrounds, and determine the total semileptonic branching fraction B(B→Xeν)=(10.34±0.04stat±0.26syst)%, averaged over B± and B0 mesons. We determine the spectrum and branching fraction for charmless B→Xueν decays and extract the CKM element |Vub|, by relying on four different QCD calculations based on the heavy quark expansion. While experimentally, the electron momentum region above 2.1 GeV/c is favored, because the background is relatively low, the uncertainties for the theoretical predictions are largest in the region near the kinematic endpoint. Detailed studies to assess the impact of these four predictions on the measurements of the electron spectrum, the branching fraction, and the extraction of the CKM matrix element |Vub| are presented, with the lower limit on the electron momentum varied from 0.8 GeV/c to the kinematic endpoint. We determine |Vub| using each of these different calculations and find, |Vub|=(3.794±0.107exp −0.219 SF+0.292 −0.068 theory+0.078)×10−3 (De Fazio and Neubert), (4.563±0.126exp −0.208 SF+0.230 −0.163 theory+0.162)×10−3 (Bosch, Lange, Neubert, and Paz), (3.959±0.104exp −0.154 SF+0.164 −0.079 theory+0.042)×10−3 (Gambino, Giordano, Ossola, and Uraltsev), (3.848±0.108exp −0.070 theory+0.084)×10−3 (dressed gluon exponentiation), where the stated uncertainties refer to the experimental uncertainties of the partial branching fraction measurement, the shape function parameters, and the theoretical calculations.
The process e+e−→π+π−2π0γ is investigated by means of the initial-state radiation technique, where a photon is emitted from the incoming electron or positron. Using 454.3 fb−1 of data collected ...around a center-of-mass energy of s=10.58 GeV by the BABAR experiment at SLAC, approximately 150000 signal events are obtained. The corresponding nonradiative cross section is measured with a relative uncertainty of 3.6% in the energy region around 1.5 GeV, surpassing all existing measurements in precision. Using this new result, the channel’s contribution to the leading order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon is calculated as (gμπ+π−2π0−2)/2=(17.9±0.1stat±0.6syst)×10−10 in the energy range 0.85 GeV<ECM<1.8 GeV. In the same energy range, the impact on the running of the fine-structure constant at the Z0-pole is determined as Δαπ+π−2π0(MZ2)=(4.44±0.02stat±0.14syst)×10−4. Furthermore, intermediate resonances are studied and especially the cross section of the process e+e−→ωπ0→π+π−2π0 is measured.
The development of drilling waste recycling technologies is a crucial task, primarily due to their negative impact on the environment, the increasing need for state control over compliance with ...environmental legislation by oil production companies, and the absence of universal technological solutions for their recycling and neutralization. This article provides a brief overview of various methods to recycle drilling waste for the production of different materials. Using drilling waste located in the Tyumen region as an example, the study demonstrates the potential of incorporating them as additives in fine-grained concrete.
We report a Dalitz plot analysis of charmless hadronic decays of charged B mesons to the final state KS0π+π0 using the full BABAR data set of 470.9±2.8 million BB¯ events collected at the Υ(4S) ...resonance. We measure the overall branching fraction and CP asymmetry to be B(B+→K0π+π0)=(31.8±1.8±2.1−0.0+6.0)×10−6 and ACP(B+→K0π+π0)=0.07±0.05±0.03−0.03+0.02, where the uncertainties are statistical, systematic, and due to the signal model, respectively. This is the first measurement of the branching fraction for B+→K0π+π0. We find first evidence of a CP asymmetry in B+→K*(892)+π0 decays: ACP(B+→K*(892)+π0)=−0.52±0.14±0.04−0.02+0.04. The significance of this asymmetry, including systematic and model uncertainties, is 3.4 standard deviations. We also measure the branching fractions and CP asymmetries for three other intermediate decay modes.
The processes e+e−→KS0K±π∓π0 and e+e−→KS0K±π∓η are studied over a continuum of energies from threshold to 4 GeV with the initial-state photon radiation method. Using 454 fb−1 of data collected with ...the BABAR detector at the SLAC PEP-II storage ring, the first measurements of the cross sections for these processes are obtained. The intermediate resonance structures from K*0(Kπ)0, K*(892)±(Kπ)∓, and KS0K±ρ∓ are studied. The J/ψ is observed in all of these channels, and corresponding branching fractions are measured.
We study the lepton forward-backward asymmetry AFB and the longitudinal K* polarization FL, as well as an observable P2 derived from them, in the rare decays B->K*l+l-, where l+l- is either e+e- or ...mu+mu-, using the full sample of 471 million BBbar events collected at the Upsilon(4S) resonance with the Babar detector at the PEP-II e+e- collider. We separately fit and report results for the B+->K*+l+l- and B0->K*0l+l- final states, as well as their combination B->K*l+l-, in five disjoint dilepton mass-squared bins. An angular analysis of B+->K*+l+l- decays is presented here for the first time.
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