This document summarizes the status of data preservation in high energy physics. The paradigms and the methodological advances are discussed from a perspective of more than ten years of experience ...with a structured effort at international level. The status and the scientific return related to the preservation of data accumulated at large collider experiments are presented, together with an account of ongoing efforts to ensure long-term analysis capabilities for ongoing and future experiments. Transverse projects aimed at generic solutions, most of which are specifically inspired by open science and FAIR principles, are presented as well. A prospective and an action plan are also indicated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A search is presented for the four-body decay B0→ppp¯p¯ in a sample of 471 million BB¯ pairs collected with the BABAR detector, operated at the SLAC PEP-II asymmetric-energy e+e− collider. The ...center-of-mass energy is 10.58 GeV. From a fit to the distribution of the energy-substituted mass mES, the branching fraction B(B0→ppp¯p¯)=(1.1±0.5±0.2)×10−7 is extracted, where the first uncertainty is statistical and the second is systematic. The significance of the signal, including the systematic uncertainty, is 2.9 standard deviations. The upper limit on the branching fraction is determined to be 2.0×10−7 at 90% confidence level.
Status and prospects of the BaBar SVT Re, V.; Bruinsma, M.; Curry, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2006, Letnik:
560, Številka:
1
Journal Article
Recenzirano
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The
BaBaR Silicon Vertex Tracker (SVT) has been efficiently operated for five years since the start of data taking in 1999. It has met design requirements and no degradation in its performance has ...been observed thus far. However, because of higher than expected background levels, and anticipated further increases in luminosity and dose rates, we have done a thorough study to assess the viability of operating the SVT until the end of the decade.
A new dark sector antibaryon, denoted ψ_{D}, could be produced in decays of B mesons. This Letter presents a search for B^{+}→ψ_{D}+p (and the charge conjugate) decays in e^{+}e^{-} annihilations at ...10.58 GeV, using data collected in the BABAR experiment. Data corresponding to an integrated luminosity of 398 fb^{-1} are analyzed. No evidence for a signal is observed. Branching fraction upper limits in the range from 10^{-7}-10^{-5} are obtained at 90% confidence level for masses of 1.0<m_{ψ_{D}}<4.3 GeV/c^{2}. The result is also reinterpreted to provide the first limits on a supersymmetric model with R-parity violation and a light neutralino.
The Silicon Vertex Tracker (SVT) of the BABAR experiment at SLAC is a crucial tool to measure with precision the decay position of B mesons produced in the PEP-II electron–positron collisions. It is ...structured in five layers made of double-sided, AC coupled silicon microstrip sensors. In this paper, a review of some of the technical solutions chosen in the detector design phase is presented. In particular, we focus here on those elements which turned out to be sources of problems during the installation and the first few years of operation; the solutions adopted to solve the problems are presented together with recommendations and proposals for alternate future designs.
We report on the first search for electron-muon lepton flavor violation (LFV) in the decay of a b quark and b antiquark bound state. We look for the LFV decay Υ(3S)→e±μ∓ in a sample of 118 million ...Υ(3S) mesons from 27 fb-1 of data collected with the BABAR detector at the SLAC PEP-II e+e- collider operating with a 10.36 GeV center-of-mass energy. No evidence for a signal is found, and we set a limit on the branching fraction BΥ(3S)→e±μ∓<3.6×10-7 at 90% C. L. This result can be interpreted as a limit ΛNP/gNP2>80 TeV on the energy scale ΛNP divided by the coupling-squared gNP2 of relevant new physics (NP).
A study of the two-body decays B^{±}→X_{ccover ¯}K^{±}, where X_{ccover ¯} refers to one charmonium state, is reported by the BABAR Collaboration using a data sample of 424 fb^{-1}. The absolute ...determination of branching fractions for these decays are significantly improved compared to previous BABAR measurements. Evidence is found for the decay B^{+}→X(3872)K^{+} at the 3σ level. The absolute branching fraction BB^{+}→X(3872)K^{+}=2.1±0.6(stat)±0.3(syst)×10^{-4} is measured for the first time. It follows that BX(3872)→J/ψπ^{+}π^{-}=(4.1±1.3)%, supporting the hypothesis of a molecular component for this resonance.
We report the observation of the rare charm decay D^{0}→K^{-}π^{+}e^{+}e^{-}, based on 468 fb^{-1} of e^{+}e^{-} annihilation data collected at or close to the center-of-mass energy of the ϒ(4S) ...resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We find the branching fraction in the invariant mass range 0.675<m(e^{+}e^{-})<0.875 GeV/c^{2} of the electron-positron pair to be B(D^{0}→K^{-}π^{+}e^{+}e^{-})=(4.0±0.5±0.2±0.1)×10^{-6}, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty in the branching fraction of the decay D^{0}→K^{-}π^{+}π^{+}π^{-} used as a normalization mode. The significance of the observation corresponds to 9.7 standard deviations including systematic uncertainties. This result is consistent with the recently reported D^{0}→K^{-}π^{+}μ^{+}μ^{-} branching fraction, measured in the same invariant mass range, and with the value expected in the standard model. In a set of regions of m(e^{+}e^{-}), where long-distance effects are potentially small, we determine a 90% confidence level upper limit on the branching fraction B(D^{0}→K^{-}π^{+}e^{+}e^{-})<3.1×10^{-6}.
The silicon vertex tracker (SVT) of the BaBar experiment at PEP-II is described. This is the crucial device for the measurement of the B meson decay vertices to extract CP-asymmetries. It consists of ...five layers of double-sided AC-coupled silicon strip detectors, read out by a full-custom integrated circuit, capable of simultaneous acquisition, digitization and transmission of data. It represents the core of the BaBar tracking system, providing position measurements with a precision of 10 /spl mu/m (inner layers) and 30/spl mu/m (outer layers). The relevant performances of the SVT are presented, and the experience acquired during the construction, installation and the first five years of data-taking is described. Innovative solutions are highlighted, like the sophisticated alignment procedure, imposed by the design of the silicon tracker, integrated in the beam-line elements and mechanically separated from the other parts of BaBar. The harshness of the background conditions in the interaction region required several studies on the radiation damage of the sensors and the front-end chips, whose results are presented. Over the next five years the luminosity is predicted to increase by a factor three, leading to radiation and occupancy levels significantly exceeding the detector design. Extrapolation of future radiation doses and occupancies is shown together with the expected detector performance and lifetime. Upgrade scenarios to deal with the increased luminosity and backgrounds are discussed.
Data preservation is a mandatory specification for any present and future experimental facility and it is a cost-effective way of doing fundamental research by exploiting unique data sets in the ...light of the continuously increasing theoretical understanding. This document summarizes the status of data preservation in high energy physics. The paradigms and the methodological advances are discussed from a perspective of more than ten years of experience with a structured effort at international level. The status and the scientific return related to the preservation of data accumulated at large collider experiments are presented, together with an account of ongoing efforts to ensure long-term analysis capabilities for ongoing and future experiments. Transverse projects aimed at generic solutions, most of which are specifically inspired by open science and FAIR principles, are presented as well. A prospective and an action plan are also indicated.
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