We present a precise measurement of the proton longitudinal double-spin asymmetry A1p and the proton spin-dependent structure function g1p at photon virtualities 0.006(GeV/c)2<Q2<1(GeV/c)2 in the ...Bjorken x range of 4×10−5<x<4×10−2. The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of 160GeV and 200GeV. The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of x, the measured values of A1p and g1p are found to be positive. It is for the first time that spin effects are found at such low values of x.
We present a new measurement of the longitudinal spin asymmetry A1d and the spin-dependent structure function g1d of the deuteron in the range 1<Q2<100 GeV2 and 0.004<x<0.7. The data were obtained by ...the COMPASS experiment at CERN using a 160 GeV polarised muon beam and a large polarised 6LiD target. The results are in agreement with those from previous experiments and improve considerably the statistical accuracy in the region 0.004<x<0.03.
We measured the longitudinal double spin asymmetries ALL for single hadron muoproduction off protons and deuterons at photon virtuality Q2<1(GeV/c)2 for transverse hadron momenta pT in the range ...1 GeV/c to 4 GeV/c. They were determined using COMPASS data taken with a polarised muon beam of 160 GeV/c or 200 GeV/c impinging on polarised 6LiD or NH3 targets. The experimental asymmetries are compared to next-to-leading order pQCD calculations, and are sensitive to the gluon polarisation ΔG inside the nucleon in the range of the nucleon momentum fraction carried by gluons 0.05<xg<0.2.
Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6LiD target. The data were taken at 160 GeV beam ...energy and the results are shown for the kinematic range 1(GeV/c)2<Q2<100(GeV/c)2 in photon virtuality, 0.004<x<0.7 in the Bjorken scaling variable and W>4GeV/c2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A1d and the deuteron longitudinal-spin structure function g1d are presented in bins of x and Q2. Towards lowest accessible values of x, g1d decreases and becomes consistent with zero within uncertainties. The presented final g1d values together with the recently published final g1p values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a0, which is identified in the MS‾ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0(Q2=3(GeV/c)2)=0.32±0.02stat±0.04syst±0.05evol. Together with the recent results on the proton spin structure function g1p, the results on g1d constitute the COMPASS legacy on the measurements of g1 through inclusive spin-dependent deep inelastic scattering.
New results for the double spin asymmetry A1p and the proton longitudinal spin structure function g1p are presented. They were obtained by the COMPASS Collaboration using polarised 200 GeV muons ...scattered off a longitudinally polarised NH3 target. The data were collected in 2011 and complement those recorded in 2007 at 160 GeV, in particular at lower values of x. They improve the statistical precision of g1p(x) by about a factor of two in the region x≲0.02. A next-to-leading order QCD fit to the g1 world data is performed. It leads to a new determination of the quark spin contribution to the nucleon spin, ΔΣ, ranging from 0.26 to 0.36, and to a re-evaluation of the first moment of g1p. The uncertainty of ΔΣ is mostly due to the large uncertainty in the present determinations of the gluon helicity distribution. A new evaluation of the Bjorken sum rule based on the COMPASS results for the non-singlet structure function g1NS(x,Q2) yields as ratio of the axial and vector coupling constants |gA/gV|=1.22±0.05 (stat.)±0.10 (syst.), which validates the sum rule to an accuracy of about 9%.
The production of
D
∗
and
D
mesons in inelastic scattering of 160 GeV/c muons off a
6
LiD target has been investigated with the COMPASS spectrometer at CERN for 0.003 (GeV/c)
2
<
Q
2
<10 (GeV/c)
2
...and 3×10
−5
<
x
Bj
<0.1. The study is based on 8100 events where a
D
0
or
is detected subsequently to a
D
∗+
or
D
∗−
decay, and on 34000 events, where only a
D
0
or
is detected. Kinematic distributions of
D
∗
,
D
and
are given as a function of their energy
E
, transverse momentum
p
T
, energy fraction
z
, and of the virtual photon variables
ν
,
Q
2
and
x
Bj
. Semi-inclusive differential
D
∗
production cross-sections are compared with theoretical predictions for
D
∗
production via photon–gluon fusion into open charm. The total observed production cross-section for
D
∗±
mesons with laboratory energies between 22 and 86 GeV is (1.9±0.4) nb. Significant cross-section asymmetries are observed between
D
∗+
and
D
∗−
production for
ν
<40 GeV and
z
>0.6.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We present a determination of the gluon polarisation I g / g in the nucleon, based on the longitudinal double-spin asymmetry of DIS events with Q 2 > 1 (GeV / c) 2 including a pair of large ...transverse-momentum hadrons in the final state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/c polarised muon beam scattering off a polarised LiD 6 target. The gluon polarisation is evaluated by a Neural Network approach for three intervals of the gluon momentum fraction x g covering the range 0.04 < x g < 0.27 . The values obtained at leading order in QCD do not show any significant dependence on x g . Their average is I g / g = 0.125 +/- 0.060 (stat.) +/- 0.063 (syst.) at average x g = 0.09 and a scale of mu 2 = 3 (GeV / c) 2 .
Introduction: A Prospective study “Spectrum of Microbial flora in diabetic foot ulcer and its antibiotic sensitivity pattern” was carried out in a tertiary care hospital, Ahmedabad on 125 patients in ...which 85 were male patients and 40 were female patients. Material and Methods: Swabs samples were collected from the edge and margins of ulcers and organism were identified by gram staining culture and biochemical reactions. Results: Out of 125 specimens 108 specimens showed growth of organisms. Total 157 aerobic organisms were isolated from culture positive specimens. It represents an average of 1.25 organisms per case. Among these organisms, 130 gram negative and 27 gram positive organisms were isolated. Pseudomonas aeruginosa (30.57%) was predominant organism followed by Klebsiella spp. (22.29%). Staphylococcus aureus were 12.74% in which Methicillin resistant S. aureus (MRSA) was 55%. Conclusion: incidence of growth was 86.4% in which Pseudomonas aeruginosa (30.57%) is most common isolate. Organisms in mixed infections showed multidrug resistance as compared to single isolated strain. Diabetic foot infections are polymicrobial in nature. As the Wagner’s grade increased, the prevalence of isolates also increased.
PDF
