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CHARGED PARTICLES HAVE LARGE ESCAPE ANGLE. DIFRACTIVE SCATTERED PION.
CHARGED PARTICLES HAVE LARGE ESCAPE ANGLE. DIFRACTIVE SCATTERED PION.
Muon pairs produced in Pb–Pb interactions at 158 GeV/ c per nucleon are used to study the transverse momentum distributions of the J/ ψ , ψ ′ and dimuons in the mass continuum. In particular, the dependence of these distributions on the centrality of the Pb–Pb collision is investigated in detail.
Mean values of PT and PT**2 calculated from the IMR distributions.
Mean values of PT and PT**2 calculated from the J/PSI distributions.
Mean values of PT and PT**2 calculated from the PSI(3685) distributions.
Phi meson production is studied by the NA49 collaboration in central Pb+Pb collisions at 20A, 30A, 40A, 80A and 158A GeV beam energy. The data are compared to measurements at lower and higher energies and to microscopic and thermal models. The energy dependence of yields and spectral distributions is compatible with the assumption that partonic degrees of freedom set in at low SPS energies.
PHI transverse momentum spectra at incident energy 20 GeV/nucleon integrated over the rapidity range 0 to 1.8.
PHI transverse momentum spectra at incident energy 30 GeV/nucleon integrated over the rapidity range 0 to 1.8.
PHI transverse momentum spectra at incident energy 40 GeV/nucleon integrated over the rapidity range 0 to 1.5.
Results on charged pion and kaon production in central Pb+Pb collisions at 20A and 30A GeV are presented and compared to data at lower and higher energies. A rapid change of the energy dependence is observed around 30A GeV for the yields of pions and kaons as well as for the shape of the transverse mass spectra. The change is compatible with the prediction that the threshold for production of a state of deconfined matter at the early stage of the collisions is located at low SPS energies.
Transverse mass spectra for pion production in the central rapidity region for collisions at 20 GeV per nucleon.
Transverse mass spectra for pion production in the central rapidity region for collisions at 30 GeV per nucleon.
Transverse mass spectra for kaon production in the central rapidity region for collisions at 20 GeV per nucleon.
The angular distributions of secondary pions, protons, and deuterons originating from π−Pb interactions at an incident-pion momentum of 5 GeV/c was determined in a new run of measurements relying on track reconstruction. While showing a decrease over a large angular interval with increasing emission angle, the yield of cumulative particles of each species was found to be anomalously large near the backward direction.
No description provided.
No description provided.
No description provided.
Transverse mass spectra of protons emitted in Au+Au collisions at beam energies of 6, 8, and 10.8 GeV/nucleon have been measured as a function of collision centrality over a rapidity range 0.5<ylab<1.5. The spectra are well reproduced by Boltzmann distributions over the measured transverse mass region, which allows for extrapolation of the data to derive the rapidity density and apparent temperature of the emitting source. The shapes of the rapidity distributions suggest significant transparency or substantial longitudinal expansion in even the most central collisions at all three beam energies. The data are analyzed within a simple thermal source plus longitudinal expansion model.
The inverse slope, mean transverse mass and rapidity density values for centrality 0 to 5 PCT for 6 GeV/nucleon collisions. Statistical errors only.
The inverse slope, mean transverse mass and rapidity density values for centrality 5 to 12 PCT for 6 GeV/nucleon collisions. Statistical errors only.
The inverse slope, mean transverse mass and rapidity density values for centrality 12 to 23 PCT for 6 GeV/nucleon collisions. Statistical errors only.
Measurements of charged pion and kaon production in central Pb+Pb collisions at 40, 80 and 158 AGeV are presented. These are compared with data at lower and higher energies as well as with results from p+p interactions. The mean pion multiplicity per wounded nucleon increases approximately linearly with s_NN^1/4 with a change of slope starting in the region 15-40 AGeV. The change from pion suppression with respect to p+p interactions, as observed at low collision energies, to pion enhancement at high energies occurs at about 40 AGeV. A non-monotonic energy dependence of the ratio of K^+ to pi^+ yields is observed, with a maximum close to 40 AGeV and an indication of a nearly constant value at higher energies.The measured dependences may be related to an increase of the entropy production and a decrease of the strangeness to entropy ratio in central Pb+Pb collisions in the low SPS energy range, which is consistent with the hypothesis that a transient state of deconfined matter is created above these energies. Other interpretations of the data are also discussed.
The centrality of the collisions expressed as a percentage of the inelastic cross section (7.15nb), and the mean numbers of wounded nuclei.
The inverse slope parameter of the fitted transverse mass spectra.
The rapidity density averaged over the rapidity interval -0.6 to 0.6.
The NA44 Collaboration has measured yields and differential distributions of K+, K-, pi+, pi- in transverse kinetic energy and rapidity, around the center-of-mass rapidity in 158 A GeV/c Pb+Pb collisions at the CERN SPS. A considerable enhancement of K+ production per pi is observed, as compared to p+p collisions at this energy. To illustrate the importance of secondary hadron rescattering as an enhancement mechanism, we compare strangeness production at the SPS and AGS with predictions of the transport model RQMD.
Inverse slope paramters of the (1/MT)*DN/DMT distribution.
Rapidity distributions for K+ and K- production.. Statistical and systematic errors added in quadrature.
Rapidity distributions for PI+ and PI- production.. Statistical and systematic errors added in quadrature.
Mid-rapidity spectra and yields of K$^-$ and K$^+$ have been measured for Au+Au collisions at 4, 6, 8, and 10.7 AGeV. The K$^-$ yield increases faster with beam energy than for K$^+$ and hence the K$^-$/K$^+$ ratio increases with beam energy. This ratio is studied as a function of both $\sqrt{s}$ and $\sqrt{s}$-$\sqrt{s_{th}}$ which allows the direct comparison of the kaon yields with respect to the production threshold in p+p reactions. For equal $\sqrt{s}$ - $\sqrt{s_{th}}$ the measured ratio K$^-$/K$^+$=0.2 at energies above threshold in contrast to the K$^-$/K$^+$ ratio of near unity observed at energies below threshold. The use of the K$^-$/K$^+$ ratio to test the predicted changes of kaon properties in dense nuclear matter is discussed.
Only statistical errors are presented.
Only statistical errors are presented.
Only statistical errors are presented.
The elastic electroproduction of phi mesons is studied at HERA with the H1 detector for photon virtualities 1 < Q^2 < 15 GeV^2 and hadronic centre of mass energies 40 < W < 130 GeV. The Q^2 and t dependences of the cross section are extracted (t being the square of the four-momentum transfer to the target proton). When plotted as function of (Q^2 + M_V^2) and scaled by the appropriate SU(5) quark charge factor, the phi meson cross section agrees within errors with the cross sections of the vector mesons V = rho, omega and J/psi. A detailed analysis is performed of the phi meson polarisation state and the ratio of the production cross sections for longitudinally and transversely polarised phi mesons is determined. A small but significant violation of s-channel helicity conservation (SCHC) is observed.
The measured ratio of PHI to RHO0 production.
The cross section for elastic PHI meson electro-production calculated by multiplying the PHI/RHO0 cross section ratio by the RHO0 cross section accurately measured in the earlier H1 publication (EPJ C13,371).
The corrected T distribution of elastic PHI meson production for W around 75 GeV and Q2 in the range 2.5 to 15 GeV**2 (mean = 4.8 GeV**2). Statistical error only.
The electroproduction of J/psi and psi(2S) mesons is studied in elastic, quasi-elastic and inclusive reactions for four momentum transfers 2 < Q^2 < 80 GeV^2 and photon-proton centre of mass energies 25 < W < 180 GeV. The data were taken with the H1 detector at the electron proton collider HERA in the years 1995 to 1997. The total virtual photon-proton cross section for elastic J/psi production is measured as a function of Q^2 and W. The dependence of the production rates on the square of the momentum transfer from the proton (t) is extracted. Decay angular distributions are analysed and the ratio of the longitudinal and transverse cross sections is derived. The ratio of the cross sections for quasi-elastic psi(2S) and J/psi meson production is measured as a function of Q^2. The results are discussed in terms of theoretical models based upon perturbative QCD. Differential cross sections for inclusive and inelastic production of J/psi mesons are determined and predictions within two theoretical frameworks are compared with the data, the non-relativistic QCD factorization approach including colour octet and colour singlet contributions, and the model of Soft Colour Interactions.
Cross section for elastic J/PSI photoproduction in W bins.
Cross section for elastic J/PSI photoproduction in W bins.
Cross section for elastic J/PSI photoproduction in W bins.
The elastic electroproduction of rho mesons is studied at HERA with the H1 detector for a photon virtuality in the range 1 < Q^2 < 60 GeV^2 and for a hadronic centre of mass energy in the range 30 < W < 140 GeV. The shape of the pipi mass distribution in the rho resonance region is measured as a function of Q^2. The full set of rho spin density matrix elements is determined, and evidence is found for a helicity flip amplitude at the level of 8 +- 3 % of the non-flip amplitudes. Measurements are presented of the dependence of the cross section on Q^2, W and t (the four-momentum transfer squared to the proton). They suggest that, especially at large Q^2, the gamma^*p cross section develops a stronger W dependence than that expected from the behaviour of elastic and total hadron-hadron cross sections.
Average values of the spin density matrix elements measured for the 1996 data sample.
Spin density matrix elements measured for 3 Q**2 values for the 1996 data sample.
Spin density matrix elements measured for 3 W values for the 1996 data sample.
K − /K + and p ¯ / p ratios measured in 158 A·GeV Pb+Pb collisions are shown as a function of transverse momentum P T and centrality in top 8.5% central region. Little centrality dependence of the K − / K + and p ¯ / p ratios is observed. The transverse mass m T distribution and dN/dy of K + , K − , p and p ¯ around mid-rapidity are obtained. The temperature T ch and the chemical potentials for both light and strange quarks (μ q , μ s ) at chemical freeze-out are determined by applying simple thermodynamical model to the present data. The resultant μ q , μ s and T ch are compared with those obtained from similar analysis of SPS S+A and AGS Si+A data. The chemical freeze-out temperature T ch at CERN energies is higher than thermal freeze-out temperature T fo which is extracted from m T distribution of charged hadrons. At AGS energies T ch is close to T fo .
Data obtained from the fit of MT spectra.
Data obtained from the fit of MT spectra.
The transverse momentum and rapidity distributions of net protons and negatively charged hadrons have been measured for minimum bias proton-nucleus and deuteron-gold interactions, as well as central oxygen-gold and sulphur-nucleus collisions at 200 GeV per nucleon. The rapidity density of net protons at midrapidity in central nucleus-nucleus collisions increases both with target mass for sulphur projectiles and with the projectile mass for a gold target. The shape of the rapidity distributions of net protons forward of midrapidity for d+Au and central S+Au collisions is similar. The average rapidity loss is larger than 2 units of rapidity for reactions with the gold target. The transverse momentum spectra of net protons for all reactions can be described by a thermal distribution with `temperatures' between 145 +- 11 MeV (p+S interactions) and 244 +- 43 MeV (central S+Au collisions). The multiplicity of negatively charged hadrons increases with the mass of the colliding system. The shape of the transverse momentum spectra of negatively charged hadrons changes from minimum bias p+p and p+S interactions to p+Au and central nucleus-nucleus collisions. The mean transverse momentum is almost constant in the vicinity of midrapidity and shows little variation with the target and projectile masses. The average number of produced negatively charged hadrons per participant baryon increases slightly from p+p, p+A to central S+S,Ag collisions.
No description provided.
No description provided.
The value YRAP = 4PI is the extrapolation for 4PI acceptance.
Strange and multistrange baryon and antibaryon production is a useful probe into the dynamics of the hot hadronic matter created in central heavy ion interactions. Relative production yields and transverse mass spectra are presented for Λ, Λ , Ξ − and Ξ + hyperons produced in central sulphur-tungsten interactions at 200 GeV/ c per nucleon.
Distributions are fitted with (1/MT**1.5)*DN/DMT=CONST*EXP(-MT/SLOPE).
No description provided.
No description provided.
The NA44 collaboration has measured charged kaon and pion distributions at midrapidity in sulphur and proton collisions with nuclear targets at 200 and 450 GeV/c per nucleon, respectively. The inverse slopes of kaons are larger than those of pions. The difference in the inverse slopes of pions, kaons and protons, all measured in our spectrometer, increases with system size and is consistent with the buildup of collective flow for larger systems. The target dependence of both the yields and inverse slopes is stronger for the sulphur beam suggesting the increased importance of secondary rescattering for SA reactions. The rapidity density, dN/dy, of both K+ and K- increases more rapidly with system size than for pi+ in a similar rapidity region. This trend continues with increasing centrality, and according to RQMD, it is caused by secondary reactions between mesons and baryons. The K-/K+ ratio falls with increasing system size but more slowly than the pbar/p ratio. The pi-/pi+ ratio is close to unity for all systems. From pBe to SPb the K+/p ratio decreases while K-/pbar increases and ({K+*K-}/{p*pbar})**1/2 stays constant. These data suggest that as larger nuclei collide, the resulting system has a larger transverse expansion, baryon density and an increasing fraction of strange quarks.
No description provided.
No description provided.
No description provided.
Photon diffractive dissociation, $\gamma p \to Xp$, has been studied at HERA with the ZEUS detector using $ep$ interactions where the virtuality $Q^2$ of the exchanged photon is smaller than 0.02 GeV$^2$. The squared four-momentum $t$ exchanged at the proton vertex was determined in the range $0.073<|t|<0.40$ GeV$^2$ by measuring the scattered proton in the ZEUS Leading Proton Spectrometer. In the photon-proton centre-of-mass energy interval $176<W<225$ GeV and for masses of the dissociated photon system $4<M_X<32$ GeV, the $t$ distribution has an exponential shape, $dN/d|t| \propto \exp{(-b|t|)}$, with a slope parameter $b=6.8 \pm 0.9$~(stat.)~$ ^{+1.2}_{-1.1}$~(syst.)~GeV$^{-2}$.
T is the squared four momentum transfer at the proton vertex.
SLOPE of the DN/DT distribution.
An analysis of theA-dependence of the target-diffractive cross-section is presented. Data on thet-dependence of the cross section are fitted in the usual exponential form. The mean multiplicity of negative particles produced diffractively is found not to be sensitive to the nuclear mass. TheA-dependence of the emitted proton multiplicity and the angular distributions of the produced charged particles suggest re-scattering of the emitted particles on other nucleons of the nucleus. All these facts are compared with results obtained by Monte-Carlo simulation according to a two-component Dual Parton Model.
For target-diffractive cross-section.
For target-diffractive cross-section.
Multiplicities for the diffractive system.
None
PRELIMINARY DATA. THE DISTRIBUTION (1/PT)*D(N)/D(PT) HAS BEEN FITTED BY A FORMULA SQRT(MT)*K1(SLOPE*MT), WHERE K1 IS THE MAKDONALD FUNCTION.
Preliminary results from WA97 measurements on Λ, Ξ and Ω production in lead-lead and proton-lead collisions are presented, along with a comparison of WA97 proton-lead data with previous WA85 proton-tungsten results. The ratio Ω gX seems to be enhanced in lead initiated reactions compared to proton initiated reactions.
No description provided.
No description provided.
PRELIMINARI DATA.
Preliminary inclusive spectra of negative hadrons, net protons and neutral strange particles are presented, measured by the NA49 experiment in central Pb+Pb collisions at 158 GeV per nucleon. Comparison of their yields with those from the lighter S+S system suggests that the yields scale approximately with the number of participating nucleons.
CENTRAL COLLISIONS, PRELIMINARY DATA.
CENTRAL COLLISIONS, PRELIMINARY DATA.
CENTRAL COLLISIONS, PRELIMINARY DATA.
Proton distributions at midrapidity have been measured for 158A·GeV Pb+Pb collisions in the focusing spectrometer experiment NA44 at CERN. A high degree of nuclear stopping is found in the truly heavy ion collisions. Systematic results of single particle transverse momentum distributions of pions, kaons, and protons, of 200A·GeV S+S and 158A·GeV Pb+Pb central collisions will be addressed within the context of thermalization. By comparing these data with thermal and transport models, freeze-out parameters such as the temperature parameter T fo and mean collective flow velocity 〈β〉 are extracted. Preliminary results of the particle ratios of K − K + and p p are discussed in the context of cascade models of RQMD and VENUS.
CENTRAL COLLISIONS: SIG(TRIG)/SIG(GEOM)=10%.
An estimate of the temperature of protons andπ− mesons in central He−Li, He−C, C−C, C−Ne, C−Cu, C−Pb, O−Pb, Mg−Mg interactions is presented. The results indicate an increase of the proton temperature with increasing mass numbers of projectile and target nuclei (Ap,AT) fromTp=(118±3) MeV for He−Li toTp=(141±2) MeV for C−Pb. The temperature ofπ− mesons does not depend onAP,AT andTπ≃95 MeV. A satisfactory fit forπ− mesons in C−Cu, C−Pb, O−Pb, Mg−Mg collisions can be achieved by using a form involving two temperatures,T1 andT2. The relative yield of the high temperature component (T2) is ≅24% for C−Cu, C−Pb, and Mg−Mg interactions. The observed results forTP in C−Ne, C−Cu and C−Pb collisions are consistent with the prediction of the thermodynamic hagedorn model.
for C-CU and C-PB YRAP=0.3-1.7.
THE D(N)/D(PT) distribution has been fitted by the form: PT*ET*K1(SLOPE*ET), where K1 is Mac-Donaldis function. for C-CU and C-PB YRAP=0.3-1.7.
No description provided.
Single particle distributions of π ± , K ± , p , p and d near mid-rapidity from 450 GeV/c p A and 200 GeV/c per nucleon SA collisions are presented. Inverse slope parameters are extracted from the transverse mass spectra, and examined for indications of collective phenomena. Proton and antiproton yields are determined for different projectile-target combinations. First results from 160 GeV/c per nucleon PbPb collisions are presented.
No description provided.
PRELIMINARY DATA FOR CENTRAL EVENTS.
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PRELIMINARY DATA FOR CENTRAL EVENTS.
Mixed transverse(P T ) momentum and rapidity distributions of charged particles produced in 200 GeV/AMU heavy ion collisions are obtained with Magnetic-Interferometric-Emulsion-Chamber ( MAGIC ) by CERN-EMU05 experiments. The P T spectra at different rapidity regions showed no anomalous enhancement of low P T components over a conventional, single exponential function with slope values ranging from 160 to 200 MeV/c.
EVENTS SELECTED FOR THE ANALYSIS ARE THOSE WITH CHARGED MULTIPLICITY MORE THAN 400 FOR CENTRAL S+PB COLLISIONS.
Multi-strange baryon and anti-baryon production is expected to be a useful probe in the search for Quark-Gluon Plasma formation. We present the transverse mass distributions of negative particles, K o s, Λs, Λ s, and Ξ − s produced in sulphurtungsten interactions at 200 GeV/c per nucleon and give the corrected ratios Λ Λ, Ξ − Λ and Ξ − /Λ . We note that our ratio Ξ − / Λ appears large in comparison to that from p p interactions.
No description provided.
No description provided.
No description provided.
The production ofK0, Λ and\(\bar \Lambda \) particles is studied in the E665 muon-nucleon experiment at Fermilab. The average multiplicities and squared transverse momenta are measured as a function ofxF andW2. Most features of the data can be well described by the Lund model. Within this model, the data on the K0/π± ratios and on the averageK0 multiplicity in the forward region favor a strangeness suppression factors/u in the fragmentation process near 0.20. Clear evidence for QCD effects is seen in the average squared transverse momentum ofK0 and Λ particles.
No description provided.
No description provided.
No description provided.
Product of charged kaons in central S + S and O + Au collisions at 200 GeV/nucleon has been studied in the NA 35 Streamer Chamber experiment. Mean multiplicities and transverse mass distributions were obtained. They were compared with nucleon-nucleon data and with model predictions.
No description provided.
No description provided.
No description provided.
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No description provided.
NET BARYON DENSITY D(N)/D(Y) HAS BEEN DETERMINED AT THE RAPIDITY OF NN C.M.S., FOR NET BARYON THE FORMULAR: 2*(P-PBAR)+1.6*(LAMBDA- LAMBDABAR) HAS BEEN USED.
No description provided.
None
CHARGED IS CUMULATIVE PI+-, OR K+-, OR P+-.
CHARGED IS CUMULATIVE PI+-, OR K+-, OR P+-.
No description provided.
None
No description provided.
No description provided.
No description provided.
None
THE AZIMUTHAL ANGLE DISTRIBUTIONS OF PI0 HAVE BEEN FITTED BY: D(N)/D(PHI)=N*(1+CONST(Q=1)*COS(PHI)+CONST(Q=2)*COS(2*PHI)), WHERE PHI IS THE AZIMUTHAL ANGLEOF PI0 RELATIVE TO THE FOLLOWING COORDINATE SYSTEM: Z AXIS DIRECTED ALONG BEAM MOMENTUM, X AXIS DIRECTED ALONG TRANSVERSE MOMENTUM CONSTRUCTED FROM TRANSVERSE MOMENTA OF THE FINAL STATE PARTICLES (SEE PAPER). THE 17 PCT OF ALL NONPERIPHERAL EVENTS HAS BEEN REMOVED (SEE PAPER).
THE AZIMUTHAL ANGLE DISTRIBUTIONS OF CHARGED PARTICLES HAVE BEEN FITTED BY : D(N)/D(PHI)=N *(1+CONST(Q=1)*COS(PHI)+CONST(Q=2)*COS(2*PHI)), WHERE PHI IS THEAZIMUTHAL ANGLE OF CHARGED PARTICLE RELATIVE TO THE FOLLOWING COORDINATE SYSTEM : Z AXIS DIRECTED ALONG BEAM MOMENTUM, X AXIS DIRECTED ALONG TRANSVERSE MOMENTU M CONSTRUCTED FROM TRANSVERSE MOMENTA OF THE FINAL STATE PARTICLES (SEE PAPER). A systematic error of 0.03 has been estimated for CONST(Q=1) and CONST(Q= 2).
THE AZIMUTHAL ANGLE DISTRIBUTIONS OF NEUTRONS HAVE BEEN FITTED BY: D(N)/D (PHI)=N *(1+CONST(Q=1)*COS(PHI)+CONST(Q=2)*COS(2*PHI)), WHERE PHI IS THE AZIMUTHAL ANGLE OF NEUTRON RELATIVE TO THE FOLLOWING COORDINATE SYSTEM: Z AXIS DIRECTEDALONG BEAM MOMENTUM, X AXIS DIRECTED ALONG TRANSVERSE MOMENTUM CONSTRUCTED FRO M TRANSVERSE MOMENTA OF THE FINAL STATE PARTICLES (SEE PAPER). A systematic error of 0.03 has been estimated for CONST(Q=1) and CONST(Q= 2).
None
No description provided.
No description provided.
MOMENTUM SPECTRA IN THE WINDOW P=0.1-6.0 HAVE BEEN FITTED BY THE FORMULA: (1/N)*D(N)/D(P)=CONST(Q=1)*EXP(-SLOPE(Q=1)*P)+CONST(Q=2)*EXP (-SLOPE(Q=2)*P).
None
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
(1/N)*D(N)/D(P) HAS BEEN FITTED BY (P/MEAN(N=P))**POWER* EXP(-SLOPE*SQRT(P/MEAN(N=P))).
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HERE XL IS CUMULATIVE NUMBER, DEFINED AS FOLLOWS: (E-PL)/M(NUCLEON). THE DISTRIBUTION (1/N)*D(N)/D(XL) WAS FITTED BY THE SUM: CONST(1)* EXP(-SLOPE(1)*XL)+CONST(2)*EXP(-SLOPE(2)*XL).
HERE XL IS CUMULATIVE NUMBER, DEFINED AS FOLLOWS: (E-PL)/M(NUCLEON). THE DISTRIBUTION (XL/N)*D(N)/D(XL) WAS FITTED BY THE SUM: CONST(1)* EXP(-SLOPE(1)*XL)+CONST(2)*EXP(-SLOPE(2)*XL).
HERE XL IS CUMULATIVE NUMBER, DEFINED AS FOLLOWS: (E-PL)/M(NUCLEON).
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43 EVENTS WITH LAMBDA, 54 EVENTS WITH KS.
43 EVENTS WITH LAMBDA, 54 EVENTS WITH KS.
43 EVENTS WITH LAMBDA, 54 EVENTS WITH KS. D(N)/D(P) WAS FITTED BY P**2*EXP(-SLOPE*EKIN).
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No description provided.
No description provided.
No description provided.
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THE SLOPE IS DETERMINED FROM THE FIT OF THE INVARIANT SPECTRUM (1/N)* (1/(2*3.14*PT))*D(N)/D(PT) BY A FORMULA MT*SUM(N=1,...) K1(N*SLOPE*MT), WHERE K1 IS MACDONALD FUNCTION.
A precise measurement of p̄p elastic scattering in the Coulomb-strong interaction interference region was performed at the CERN Sp̄pS Collider at a centre-of-mass energy of 541 GeV. The ratio of the real to the imaginary part of the forward elastic scattering amplitude was found to be ρ = 0.135 ± 0.015. The slope of the exponential fall off of the strong interaction part was also measured to be b = 15.5 ± 0.1 GeV −2 .
No description provided.
Real part of amplitude extracted using a more precise UA4 measurement. (1 +RE(AMP)/IM(AMP)**2)SIG(TOT) = 63.5 +- 1.5 MB (Bozzo et al. PL 147B(1984)392).
The reaction π−p→η′η′n has been studied atpπ=37 GeV/c. Total of 14 events of this reaction have been selected. It has been shown that in the effective mass spectrum of the η′η′ system the events are concentrated mainly near the reaction threshold, which might be caused by the decayX(1910)→η′η′. The reaction cross-section has been evaluated: σ(π−p→η′η′n)=110±40 nb.
No description provided.
No description provided.
We present measurements of the rapidity and transverse-momentum distributions of the protons emitted in S+W, O+W, andp+W reactions at 200 GeV/A around the target rapidity (y=1). The rapidity density rises linearly with the transverse energy for all three systems, but the slope forp+W is much steeper than for O+W and S+W. The rapidity density forp+W is much higher than predicted by summing single nucleonnucleon collisions without any nuclear effects, indicating substantial rescattering of the produced particles. The predictions of the VENUS 3 model, including rescattering, show reasonable agreement with the data for all three systems. We do not have evidence for a strong collective flow of the outgoing particles.
No description provided.
No description provided.
No description provided.
Light ion collisions with carbon target at 4.2 GeV/c/N are studied. Pion multiplicity distributions, momentum and angular spectra are analysed. These data are described in terms of models assuming independent interactions of nucleons from the projectile nucleus with the target.
No description provided.
No description provided.
No description provided.
Longitudinal and transverse momentum spectra of final state hadrons produced in deep-inelastic muon-deuterium scattering at incident muon energy of 490 GeV have been measured up to a hadronic center of mass energy of 30 GeV. The longitudinal distributions agree well with data from earlier muon-nucleon scattering experiments; these distributions tend to increase in steepness as the center of mass energy increases. Comparisons with e + e − data at comparable center of mass energies indicate slight differences. The transverse momentum distributions show an increase in mean p T 2 with an increase in the center of mass energy.
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
'CHARGED EXCHANGED REACTION', MOMENTUM OF N IS GREATER THAN MOMENTUM OF EACH PROTON.
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AUTHORS FIT D2(SIG)/D(XL)/D(PT**2) BY (1-XL)**POWER*EXP(-SLOPE*PT**2).
AUTHORS FIT D2(SIG)/D(XL)/D(PT**2) BY (1-XL)**POWER*EXP(-SLOPE*PT**2).
AUTHORS FIT D2(SIG)/D(XL)/D(PT**2) BY (1-XL)**POWER*EXP(-SLOPE*PT**2).
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BEAM NUCLEUS ARE MIXTURE OF NE AND MG.
BEAM NUCLEUS ARE MIXTURE OF NE AND MG.
BEAM NUCLEUS ARE MIXTURE OF NE AND MG.
We have studied proton-antiproton elastic scattering at s=1800 GeV at the Fermilab Collider, in the range 0.02<|t|<0.13 (GeV/c)2. Fitting the distribution by exp(−B|t|), we obtain a value of B of 17.2±1.3 (GeV/c)−2.
No description provided.
Error contains estimate of systematic effects.
Forum