3,474 research outputs found
Early ATLAS B-physics with the first 10 – 100 pb-1
Early data of ATLAS will allow several B-physics measurements. Already with few pb-1 the ratio of the cross section of prompt J/ψ to indirect J/ψ cross-section will be measured with statistical precision of <5%. With 10 pb−1, the cross section of heavy quarkonia like J/Ψ and Y will be measured in a pT range from 10-50 GeV/c. The J/y and Y polarization is expected to be measured with a precision of 0.02 to 0.06 and 0.2 for Y, respectively. Another measurement with first data will be the estimation of the cross section of the exclusive decay B+ →J/yK+, which will be used as a reference channel for e.g. rare B-decay searches as well as for detector performance studies. The measurement of the invariant masses of the B-mesons and lifetimes using these decays will allow detector performance checks
Early ATLAS B-physics with the first 10 - 100 pb-1
The B-physics program of the ATLAS experiment at the LHC with the early data is presented. These data will allow us to measure the production cross sections for B hadrons and heavy quarkonia in pp collisions at a center-of-mass energy of 14 TeV to a reasonable precision. The B-physics trigger scheme employing single or di-muon algorithms is discussed. The potential for extracting the polarization of vector states from the decays J/ψ→ μ+μ− and Υ→ μ+μ− is also presented
Analysis of the volatile organic compound fingerprint of Greek grape marc spirits of various origins and traditional production styles
The most well-known traditional Greek grape marc distillate made from winemaking pomace is called “Tsipouro”. Its production involves various grape pomace cultivars, preparation protocols, and anise-flavoring or not, and it should be a colorless liquid with intense organoleptic properties due to the raw materials used in its production and have a minimum alcoholic strength of 37.5% by volume. This study aimed to characterize the volatilome of tsipouro products by covering as many geographical areas and production styles as possible, as there is a lack of characterization of the aromatic composition of this Greek traditional alcoholic beverage. A Headspace Solid Phase Microextraction Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS) method was applied in 60 samples, resulting in the identification and semi-quantification of over 90 volatile compounds. The statistical analysis pointed out the metabolites that characterized each traditional product group and underlined the influence of the geographical origin and the production protocol. Aniseed spirits from Northern Greece, Macedonia, Limnos Island, and Thessaly, produced from Muscat pomaces, were found to be richer in terpenes, terpenoids, and flavored compounds, attributing to product aroma and quality; different terpenoids were found to be dominant in Muscat distillates from different regions, showing the importance of geographical origin and production process. In conclusion, the results demonstrated the high aroma variability of the Greek Tsipouro, explained that this diversity is caused mainly by the raw material, and could be helpful in the better protection of the origin of this traditional product and the improvement of its qualit
Fragmentation cross sections of 158 A GeV Pb ions in various targets measured with CR39 nuclear track detectors
We report the measurement of the fragmentation cross sections in high-energy
nucleus-nucleus collisions using the 158 A GeV Pb beam from the CERN-SPS. The
fragments have charges changed from that of the incident projectile nucleus by
, with 8 <\Delta Z <75. The targets range from
polyethylene to lead. Charge identification is made with CR39 nuclear track
detectors, measured with an automatic image analyzer system. The measured
fragmentation cross sections are parameterized with an empirical relation in
terms of the atomic mass of the target, and of the charge of the final
fragment.Comment: 16 pages, 5 figure
Search for charginos in e+e- interactions at sqrt(s) = 189 GeV
An update of the searches for charginos and gravitinos is presented, based on
a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector
in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was
found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a
centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by
combining the chargino searches with neutralino searches at the Z resonance
implies a limit on the mass of the lightest neutralino which, for a heavy
sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure
Search for composite and exotic fermions at LEP 2
A search for unstable heavy fermions with the DELPHI detector at LEP is
reported. Sequential and non-canonical leptons, as well as excited leptons and
quarks, are considered. The data analysed correspond to an integrated
luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV
and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172
GeV and 161 GeV. The search for pair-produced new leptons establishes 95%
confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2,
depending on the channel. The search for singly produced excited leptons and
quarks establishes upper limits on the ratio of the coupling of the excited
fermio
Search for lightest neutralino and stau pair production in light gravitino scenarios with stau NLSP
Promptly decaying lightest neutralinos and long-lived staus are searched for
in the context of light gravitino scenarios. It is assumed that the stau is the
next to lightest supersymmetric particle (NLSP) and that the lightest
neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector
at centre-of-mass energies from 161 to 183 \GeV are analysed. No evidence of
the production of these particles is found. Hence, lower mass limits for both
kinds of particles are set at 95% C.L.. The mass of gaugino-like neutralinos is
found to be greater than 71.5 GeV/c^2. In the search for long-lived stau,
masses less than 70.0 to 77.5 \GeVcc are excluded for gravitino masses from 10
to 150 \eVcc . Combining this search with the searches for stable heavy leptons
and Minimal Supersymmetric Standard Model staus a lower limit of 68.5 \GeVcc
may be set for the stau mas
Hadronization properties of b quarks compared to light quarks in e+e- -> q qbar from 183 to 200 GeV
The DELPHI detector at LEP has collected 54 pb^{-1} of data at a
centre-of-mass energy around 183 GeV during 1997, 158 pb^{-1} around 189 GeV
during 1998, and 187 pb^{-1} between 192 and 200 GeV during 1999. These data
were used to measure the average charged particle multiplicity in e+e- -> b
bbar events, _{bb}, and the difference delta_{bl} between _{bb} and the
multiplicity, _{ll}, in generic light quark (u,d,s) events: delta_{bl}(183
GeV) = 4.55 +/- 1.31 (stat) +/- 0.73 (syst) delta_{bl}(189 GeV) = 4.43 +/- 0.85
(stat) +/- 0.61 (syst) delta_{bl}(200 GeV) = 3.39 +/- 0.89 (stat) +/- 1.01
(syst). This result is consistent with QCD predictions, while it is
inconsistent with calculations assuming that the multiplicity accompanying the
decay of a heavy quark is independent of the mass of the quark itself.Comment: 13 pages, 2 figure
Search for supersymmetric particles in scenarios with a gravitino LSP and stau NLSP
Sleptons, neutralinos and charginos were searched for in the context of
scenarios where the lightest supersymmetric particle is the gravitino. It was
assumed that the stau is the next-to-lightest supersymmetric particle. Data
collected with the DELPHI detector at a centre-of-mass energy near 189 GeV were
analysed combining the methods developed in previous searches at lower
energies. No evidence for the production of these supersymmetric particles was
found. Hence, limits were derived at 95% confidence level.Comment: 31 pages, 14 figure
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