We report results from a measurement of the inclusive processes pp→Xp and pd→Xd in the range 5<Mx2s<0.1, 0.01≲|t|≲0.1 (GeV/c)2, and incident proton momenta of 65, 154, and 372 GeV/c. Both pp and pd data show an exponential t dependence and a dominant 1Mx2 behavior for Mx2s≲0.05. By comparing pp and pd data we test factorization and, using the Glauber model, we measure the XN total cross section, σXN=43±10 mb.
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We have measured p−d inelastic scattering at small momentum transfer by detecting the slow-recoil deuterons from a deuterium-gas-jet target. The coherent diffraction dissociation of protons on deuterons was studied in the region 0.03<|t|<0.07 (GeV/c)2, 1.4<MX2<4 GeV2, and for energies from 50 to 275 GeV. In this region, the diffractive cross section exhibits structure and is dominated by an enhancement at MX2∼1.9 GeV2.
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We report results from a measurement of the inclusive process p+d→X+d in the region 0.03<|t|<0.12 (GeV/c)2 and 5 GeV2<MX2≲0.11plab for incident proton momenta from 150 to 400 GeV/c. We find that in this region, the differential cross section d2σdtdMX2 varies only slowly with energy, falls exponentially with |t|, and behaves to a good approximation as 1MX2. The measurement was performed at Fermilab by detecting slow-recoil deuterons from a deuterium-gas-jet target placed at the internal beam of the accelerator.
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Proton-deuteron elastic scattering has been measured in the four-momentum transfer squared region 0.013<|t|<0.14 (GeV/c)2 and for incident proton beam momenta from 50 to 400 GeV/c. The data can be fitted with the Bethe interference formula. We observe shrinkage of the diffraction cone with increasing energy equal to (0.94±0.04)ln(s1 GeV2) (GeV/c)−2. This shrinkage is greater than that observed in pp elastic scattering. The ratio of the elastic to the total cross section is approximately 0.1 and independent of energy above ∼ 150 GeV. In order to extract information on pn scattering we fit our data using the Glauber approach and a form factor which is the sum of exponentials. The values we obtain for the slope parameter in pn scattering are sensitive to the details of the inelastic double-scattering term.
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We have measured the differential cross section for small angle p−p scattering from 25 to 200 GeV incident energy and in the momentum transfer range 0.015<|t|<0.080 (GeVc)2. We find that the slope of the forward diffraction peak, b(s), increases with energy and can be fitted by the form b(s)=b0+2α′ lns, where b0=8.3±1.3 and α′=0.28±0.13 (GeVc)−2. Such dependence is compatible with the data existing both at higher and lower energies. We have also obtained the energy dependence of the p−p total cross section in the energy range from 48 to 196 GeV. Within our errors which are ± 1.1 mb the total cross section remains constant.
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THE TOTAL CROSS SECTION IS NORMALIZED TO 38.5 +- 0.1 MB AT 48 GEV. IT HAS BEEN DERIVED USING THE OPTICAL THEOREM FROM THE EXTRAPOLATED FORWARD ELASTIC CROSS SECTION AND WITH ALPHA = -0.09.
The differential cross sections for γ p→ π + n from hydrogen and the π − π + ratios from deuterium were measured at nine c.m. angles between 30° and 150° for laboratory photon energies between 260 and 800 MeV. A magnetic spectrometer with three layers of scintillation hodoscope was used to detect charged π mesons. The cross section for γ n→ π − p was obtained as a product of d σ d Ω (γ p →π + n ) and the π − π + ratio. The overall features in the cross sections of the two reactions, γ p→ π + n and γ n→ π − p, and in the ratios, π − π + , agree with predictions by Moorhouse, Oberlack and Rosenfeld, and Metcalf and Walker. An investigation of the possible existence of an isotensor current was made and a negative result was found. In detailed balance comparison with the new results on the inverse reaction π − p→ γ n, no apparent violation of time-reversal invariance was observed.
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The tensor analyzing power T20 for the reaction d↑+12C→p(0°)+X has been measured in the region of proton internal momenta k in light-cone dynamics up to 1 GeV/ c. Measurements have been carried out at Dubna Synchrophasotron with polarized deuteron beam at deuteron momenta up to 9 GeV/ c. When k increases the experimental values of T20 have a tendency to approach the value ( −0.3) obtained by the calculation based on the reduced nuclear amplitude method in which the quark degrees of freedom are taken into account.
The momentum K, called momentum in light-cone dynamics, is expressed by thefollowing formula k**2=mt**2/(4*alpha*(1-alpha))-m**2,with mt**2=kt**2+m**2 wh ere kt is the proton transverse momentum.The light-cone variable alpha is the p art of the deuteron momentum carried by the proton in the infinite momentum frameand is expressed by the formula alpha=(Ep+Pp)/(Ed+Pd).
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ABS(COS(THETA)) < 0.4 for M(P=3 4) = 1.025 GeV.
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A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2012 at $\sqrt{s}$=8 TeV from $pp$ collisions corresponding to an integrated luminosity of $20.3$ fb$^{-1}$ are examined. Particles producing anomalously high ionisation, consistent with long-lived massive particles with electric charges from $|q|=2e$ to $|q|=6e$ are searched for. No signal candidate events are observed, and 95\% confidence level cross-section upper limits are interpreted as lower mass limits for a Drell--Yan production model. The mass limits range between 660 and 785 GeV.
The observed event yield in data in the B region, the probability $f$ to find a particle above the respective $S$(MDT dE/dx) value before tight selection and the expected background yield in the signal region D with its statistical uncertainty. The last column shows the observed event yield in the D region.
Fractions of signal events (in %) with at least one multi-charged particle, which satisfy the given requirements. The uncertainties quoted are statistical.
Overview of separate contributions (in %) to the systematic uncertainty on the signal. The total uncertainty is given by the quadratic sum of the individual uncertainties.
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