Nucl. Instrum. Meth. A

The first combined test of an electromagnetic liquid argon accordion calorimeter and a hadronic scintillating-tile calorimeter was carried out at the CERN SPS. These devices are prototypes of the barrel calorimeter of the future ATLAS experiment at the LHC. The energy resolution of pions in the energy range from 20 to 300 GeV at an incident angle θ of about 11° is well-described by the expression σ E = (( 46.5 ± 6.0% √E+(1.2±0.3)% ) ⊕ (3.2±0.4) GeV E . Shower profiles, shower leakage, and the angular resolution of hadronic showers were also studied.

Phys. Lett. B

The production of antiprotons in $pp$ collisions is investigated close to threshold where experimental data about the total cross section are not available. We analyze the latter reaction within the LUND string model for inclusive $\bar{p}$ production and within the framework of a one-boson exchange model for the exclusive reaction $pp \rightarrow ppp\bar{p}$. The application of our new results to the analysis of subthreshold antiproton production in $d + p$ and $d + d$ collisions shows cross sections that are much lower than expected before. Nevertheless, the comparison of experimental $\bar{p}$ differential cross sections from $d +p$ and $d + d$ is expected to provide valuable information about a nonnucleonic component in the deuteron wavefunction.

Z. Phys. C

The energy loss spectrum of 150 GeV muons has been measured with a prototype of the ATLAS hadron calorimeter in the H8 beam of the CERN SPS. The differential probability dP/dv per radiation length of a fractional energy loss v = ΔEμ/Eμ has been measured in the range v = 0.01 ÷ 0.95; it is compared with the theoretical predictions for energy losses due to bremsstrahlung and production of electron—positron pairs or of energetic knock-on electrons. The integrated probability \(\int_{0.01}^{0.95}({\rm d}P/{\rm d}v){\rm d}v\) is (1.610 ± 0.015stat ± 0.105syst) · 10−3 in agreement with the theoretical predictions 1.556 · 10−3 and 1.619 · 10−3. Agreement with theory is also found in two intervals of v where production of electron-positron pairs and knock-on electrons dominates. In the region of bremsstrahlung dominance (v = 0.12 ÷ 0.95) the measured integrated probability (1.160 ± 0.040stat ± 0.075syst) · 10−4 is in agreement with the theoretical value of 1.185 · 10−4, obtained using the Petrukhin and Shestakov description of the bremsstrahlung process. The same result is about 3.6 standard deviations (defined as the quadratic sum of statistical and systematic errors) lower than the theoretical prediction of 1.472 · 10−4, obtained using Tsai’s description of bremsstrahlung.

JETP Lett.

It is shown that the calculation of the Mott corrections to the Bethe-Bloch formula can be reduced to summation of a series whose terms are bilinear in the Mott partial amplitudes.

Nucl. Instrum. Meth. A

We present the results of measurements of the light yield dependencies for the plastic scintillators on magnetic field value and orientation. The magnetic field value was changed from 0 up to 3.8 T. Scintillators were irradiated by electrons ( 137 Cs and 207 Bi) and by alpha-particles ( 241 Am). The detected light spectra in the electron irradiating cases show two dependencies: the first one is dependence on the magnetic field value only and the second-light output is dependent on the magnetic field orientation when the radioactive source is outside of the scintillator. The value and behavior of the first dependence agree with data published earlier.

Nucl.Instrum.Meth.A

A movable polarized target has a volume 140 cm 3 (20 cm long and 3 cm diameter). Polarizing magnet was tested to 6.5T, homogeneity is better than 2 × 10 −4 . The nuclear spin relaxation time in a frozen mode (at a temperature 50 mK and magnetic field 2.5T) is over 1000 h. Maximum values of proton polarization obtained were 80% and 85% for positive and negative polarization, respectively.

Nucl. Instrum. Meth. A

The design and characteristics of two-coordinate cylindrical multiwire proportional chambers manufactured in JINR (Dubna) for experimental investigation of the π + →π 0 e + ν e decay are described.

Surveys High Energ. Phys.

Z.Phys.C

Results of the total cross section differenceΔσL in anp transmission experiment at 1.19, 2.49 and 3.65 GeV incident neutron beam kinetic energies are presented. Measurements were performed at the Synchrophasotron of the Laboratory of High Energies of the Joint Institute for Nuclear Research in Dubna. Results were obtained with a polarized beam of free quasi-monochromatic neutrons passing through the new Dubna frozen spin proton target. The beam and target polarizations were oriented longitudinally. The present results were obtained at the highest energies of free polarized neutrons that can be reached at present. They extend the energy range of existing results from PSI, LAMPF and Saclay measured between 0.066 and 1.10 GeV. The new results are compared withΔσL(pn) data determined as a difference betweenΔσL(pd) andΔσL(pp) ANL-ZGS measurements. The values ofΔσL for the isospin stateI=0 were deduced using knownpp data.

Phys.Lett.B

The experiment on the search for inclusive electron neutrino oscillations is being carried out at the special neutrino beam of the Serpukhov 70 GeV accelerator using the IHEP-JINR neutrino detector. The short decay cavity of the neutrino beam makes it possible to search for oscillations analyzing the shape of the distribution of events using the variable L E , where L is the distance from the point of origin to the point of interaction of neutrino, E is the neutrino energy.

J. Nonlin. Math. Phys.

The solutions of Heisenberg equations and two-particles eigenvalue problems for nonrelativistic models of current-current fermion interaction and $N, \Theta $ model are obtained in the frameworks of dynamical mapping method. The equivalence of different types of dynamical mapping is shown. The connection between renormalization procedure and theory of selfadjoint extensions is elucidated.

Z. Phys. C

The NEMO-2 tracking detector located in the Fréjus Underground Laboratory was designed as a prototype of the detector NEMO-3 to study 0ν and 2ν double-beta decay (ββ) physics. After ten months of nearly continuous running with an enriched cadmium source (0.92 mol·y of116Cd) aββ2ν half-life ofT1/2=(3.75±0.35(stat)±0.21(syst))·1019 y was measured. Limits with 90% CL on the116Cd half-lives of 5.0·1021 y forββ0ν decay and of 1.2·1021 y forββ0νχ0 decay with a Majoron (χ0) were obtained. Theoretical predictions for 0ν and 2ν decays of116Cd are also presented.

Nucl. Phys. A

The two-body transfer mechanism for elastic rearrangement scattering from the three-body bound state i + { jkl } → j + { ikl } has been investigated on the basis of 4-dimensional formalism of covariant nonrelativistic graphs. The relation between this approach and the 3-dimensional graph formalism has been analyzed in detail. This approach is applied to describing backward elastic p 3 He scattering in the energy range 0.5 – 1.7 GeV. The Faddeev 5-channel wave function is used for the bound state of the 3 He nucleus. Numerical calculations show that the mechanism of sequential transfer of a noninteracting np-pair dominates while transfer of an interacting pair as well as nonsequential transfer of a noninteracting np-pair give a negligible contribution. The dominating mechanism is insensitive to the D-components of the 3 He wave function and relativistic effects in spite of high momentum transfer. Taking into consideration Glauber rescatterings in the entrance and exit channels one obtains agreement with the experimental data in energy and angular dependence of the differential cross section at energies 0.9 – 1.7 GeV.

JETP Lett.

It is shown that a two-step model of the reaction pd→3HeX (X=η, η′ eω, φ), involving the subprocesses pp) →dπ+ and π+n→Xp, can account for the form of the energy dependence of experimental cross sections above the thresholds under the assumption that the singlet part of the pp→dπ+ amplitude dominates. The spin-spin asymmetry for the reaction dp→3HeX has been found to be ∼;−1 in the forward-backward approximation.