Abstract The physics goal of the strong interaction program of the NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) is to study the phase diagram of hadronic matter by a scan of ...particle production in collisions of nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents differential inclusive spectra of transverse momentum, transverse mass and rapidity of $$\pi ^{-}$$ π - mesons produced in central $^{40}$$ 40 Ar+ $^{45}$$ 45 Sc collisions at beam momenta of 13A, 19A, 30A, 40A, 75A and 150 $$A\,\text{ Ge }\text{ V }\!/\!\textit{c}$$ A Ge V / c . Energy and system size dependence of parameters of these distributions – mean transverse mass, the inverse slope parameter of transverse mass spectra, width of the rapidity distribution and mean multiplicity – are presented and discussed. Furthermore, the dependence of the ratio of the mean number of produced pions to the mean number of wounded nucleons on the collision energy was derived. The results are compared to predictions of several models.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract The NA61/SHINE experiment at the CERN Super Proton Synchrotron (SPS) studies the onset of deconfinement in hadron matter by a scan of particle production in collisions of nuclei with various ...sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra, transverse momentum and rapidity distributions and mean multiplicities of $$\pi ^\pm $$ π ± , $$K^\pm $$ K ± , p and $$\bar{p}$$ p ¯ produced in the 20% most central $$^7$$ 7 Be+ $$^9$$ 9 Be collisions at beam momenta of 19A, 30A, 40A, 75A and 150A $${\mathrm{Ge} \mathrm{V}}\!/\!c$$ Ge V / c . The energy dependence of the $$K^\pm $$ K ± / $$\pi ^\pm $$ π ± ratios as well as of inverse slope parameters of the $$K^\pm $$ K ± transverse mass distributions are close to those found in inelastic p+p reactions. The new results are compared to the world data on p+p and Pb+Pb collisions as well as to predictions of the Epos, Urqmd, Ampt, Phsd and Smash models.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract A measurement of charged hadron pair correlations in two-dimensional $$\Delta \eta \Delta \phi $$ Δ η Δ ϕ space is presented. The analysis is based on total 30 million central Be + Be ...collisions observed in the NA61/SHINE detector at the CERN SPS for incident beam momenta of 19A, 30A, 40A, 75A, and 150A $$\text {Ge} \text {V}/c$$ Ge / c . Measurements were carried out for unlike-sign and like-sign charge hadron pairs independently. The $$C(\Delta \eta ,\Delta \phi )$$ C ( Δ η , Δ ϕ ) correlation functions were compared with results from a similar analysis on p + p interactions at similar beam momenta per nucleon. General trends of the back-to-back correlations are similar in central Be + Be collisions and p + p interactions, but are suppressed in magnitude due to the increased combinatorial background. Predictions from the Epos and UrQMD models are compared to the measurements. Evolution of an enhancement around $$(\Delta \eta ,\Delta \phi ) = (0,0)$$ ( Δ η , Δ ϕ ) = ( 0 , 0 ) with incident energy is observed in central Be + Be collisions. It is not predicted by both models and almost non-existing in proton–proton collisions at the same momentum per nucleon.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
For the first time, the Faraday method is used to measure the temperature dependence of paramagnetic susceptibility χ(T) of (La^sub 1 - x^Sr^sub x^)^sub 0.93^MnO^sub 3^ (x = 0.2, 0.25, or 0.3) ...manganites in the temperature interval 60-850°C. It is demonstrated that the dependences have two kinks and three linear sections. The kink of curve χ^sup -1^(T) is related to polymorphic transformations (Q' arrow right Q* and Q* arrow right R) that take place in the crystal lattices of the samples. The main magnetic characteristics of the samples are determined with the least-squares processing of curve χ^sup -1^. Is is demonstrated that dependence χ^sup -1^(T) obeys the Curie-Weiss law. The energy state of the magnetoactive manganese atom in the Q'-and Q*-phase samples is close to the energy state of a free Mn^sup 2+^ ion. In the R phase, this state is close to the state of a free Mn^sup 3+^ ion.PUBLICATION ABSTRACT
Full text
Available for:
CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract The NA61/SHINE collaboration studies at the CERN Super Proton Synchrotron (SPS) the onset of deconfinement in hadronic matter by the measurement of particle production in collisions of ...nuclei with various sizes at a set of energies covering the SPS energy range. This paper presents results on inclusive double-differential spectra and mean multiplicities of $$\pi ^{-}$$ π - mesons produced in the 5% most central $$^7$$ 7 Be + $$^9$$ 9 Be collisions at beam momenta of 19A, 30A, 40A, 75A and 150 $$A\,\text{ GeV }\!/\!c$$ A GeV / c obtained by the so-called $$h^-$$ h - method which does not require any particle identification. The shape of the transverse mass spectra differs from the shapes measured in central Pb + Pb collisions and inelastic p+p interactions. The normalized width of the rapidity distribution decreases with increasing collision energy and is in between the results for inelastic nucleon–nucleon and central Pb + Pb collisions. The mean multiplicity of pions per wounded nucleon in central $$^7$$ 7 Be + $$^9$$ 9 Be collisions is close to that in central Pb + Pb collisions up to 75 $$A\,\text{ GeV }\!/\!c$$ A GeV / c . However, at the top SPS energy the result lies between those for nucleon–nucleon and Pb + Pb interactions. The results are discussed in the context of predictions for the onset of deconfinement at the CERN SPS collision energies.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Very simple solution of the coupled partial differential equations that leads to analytic formula for diffraction efficiency which describes the time dependence of four-wave mixing in photorefractive ...crystals is presented. The obtained results were used for analysis of simultaneous read–write dynamics in Bi12SiO20 crystal.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract The production of $$\Xi (1321)^{-}$$ Ξ ( 1321 ) - and $$\overline{\Xi }(1321)^{+}$$ Ξ ¯ ( 1321 ) + hyperons in inelastic p+p interactions is studied in a fixed target experiment at a beam ...momentum of 158 $$\hbox {Ge}\hbox {V}\!/\!c$$ Ge / c . Double differential distributions in rapidity $${y}$$ y and transverse momentum $$p_{T}$$ p T are obtained from a sample of 33M inelastic events. They allow to extrapolate the spectra to full phase space and to determine the mean multiplicity of both $${\Xi }{^-} $$ Ξ - and $$\overline{\Xi }{^+} $$ Ξ ¯ + . The rapidity and transverse momentum spectra are compared to transport model predictions. The $${\Xi }{^-} $$ Ξ - mean multiplicity in inelastic p+p interactions at 158 $$\hbox {Ge}\hbox {V}\!/\!c$$ Ge / c is used to quantify the strangeness enhancement in A+A collisions at the same centre-of-mass energy per nucleon pair.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We present data on dielectron emission in proton induced reactions on a Nb target at 3.5 GeV kinetic beam energy measured with HADES installed at GSI. The data represent the first high statistics ...measurement of proton-induced dielectron radiation from cold nuclear matter in a kinematic regime, where strong medium effects are expected. Combined with the good mass resolution of 2%, it is the first measurement sensitive to changes of the spectral functions of vector mesons, as predicted by models for hadrons at rest or small relative momenta. Comparing the e+e− invariant mass spectra to elementary p+p data, we observe for e+e− momenta Pee<0.8 GeV/c a strong modification of the shape of the spectrum, which we attribute to an additional ρ-like contribution and a decrease of ω yield. These opposite trends are tentatively interpreted as a strong coupling of the ρ meson to baryonic resonances and an absorption of the ω meson, which are two aspects of in-medium modification of vector mesons.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The tagged quasi-free np→npπ+π− reaction has been studied experimentally with the High Acceptance Di-Electron Spectrometer (HADES) at GSI at a deuteron incident beam energy of 1.25 GeV/nucleon ...(s∼2.42 GeV/c for the quasi-free collision). For the first time, differential distributions of solid statistics for π+π− production in np collisions have been collected in the region corresponding to the large transverse momenta of the secondary particles. The invariant mass and angular distributions for the np→npπ+π− reaction are compared with different models. This comparison confirms the dominance of the t-channel with ΔΔ contribution. It also validates the changes previously introduced in the Valencia model to describe two-pion production data in other isospin channels, although some deviations are observed, especially for the π+π− invariant mass spectrum. The extracted total cross section is also in much better agreement with this model. Our new measurement puts useful constraints for the existence of the conjectured dibaryon resonance at mass M∼2.38 GeV and with width Γ∼70 MeV.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
