We report results on an elastic cross section measurement in proton-proton collisions at a center-of-mass energy $\sqrt{s}=510$ GeV, obtained with the Roman Pot setup of the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The elastic differential cross section is measured in the four-momentum transfer squared range $0.23 \leq -t \leq 0.67$ GeV$^2$. We find that a constant slope $B$ does not fit the data in the aforementioned $t$ range, and we obtain a much better fit using a second-order polynomial for $B(t)$. The $t$ dependence of $B$ is determined using six subintervals of $t$ in the STAR measured $t$ range, and is in good agreement with the phenomenological models. The measured elastic differential cross section $\mathrm{d}\sigma/\mathrm{dt}$ agrees well with the results obtained at $\sqrt{s} = 546$ GeV for proton--antiproton collisions by the UA4 experiment. We also determine that the integrated elastic cross section within the STAR $t$-range is $\sigma^\mathrm{fid}_\mathrm{el} = 462.1 \pm 0.9 (\mathrm{stat.}) \pm 1.1 (\mathrm {syst.}) \pm 11.6 (\mathrm {scale})$~$\mu\mathrm{b}$.
Top panel: The $pp$ elastic differential cross section $d\sigma/dt$ fitted with an exponential $A e^{-B(t)|t|}$. Bottom panel: Residuals (Data - Fit)/Error. Uncertainties on the data points are smaller than the symbol size. The vertical scale uncertainty of 2.5% is not included in in the full error.
Results of the exponential function $A e^{-B(t)|t|}$ fit to the elastic differential cross section data as well as the integrated fiducial cross section are listed. Also listed are the corresponding values of the statistical and systematic uncertainties. The scale (luminosity and trigger efficiency) uncertainty of 2.5% applicable to the fit parameter $A$ and fiducial cross section $\sigma^\mathrm{fid}_\mathrm{el}$ is not included in the full error.
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X ERROR D(THETA) =0.5000MRAD AND D(P)/P = 0.700PCT.
X ERROR D(THETA) =0.5000MRAD AND D(P)/P = 0.700PCT.
X ERROR D(THETA) =0.5000MRAD AND D(P)/P = 0.700PCT.
The absolute differential cross sections of 17.9 GeV/$c$ $\alpha$-particles scattering on nuclear targets have been measured over a four momentum transfer range of $0.009
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INTEGRATED D(SIG)/D(T).
OBTAINED FROM FIT D(SIG)/D(T)=A*EXP(B*T+C*T**2) IN 0.05 < -T < 0.3.
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The absolute differential cross sections for ap elastic scattering and for the sum of elastic and quasielastic aa scattering have been measured at a momentum of 17.9 GeV/c in the four-momentum transfer region (0.01 < | t | < 0.2) GeV2/c2 with normalization errors less than 3%. Such measurements in the energy region of a few GeV have been performed for the first time. The measurements have been carried out using the alpha particle beam with the intensity of (1-5)x105 particles/s extracted from the synchrophasotron during 0.3-0.5s. The cryogen target filled with hydrogen (0.847+-0.001 g/cm2) and helium was used. The substance amount along the particle path constituted 0.11 g/cm2 in an unfilled target. The total cross sections, diffraction cone slope parameters and total elastic cross sections for ap and aa scattering have been obtained. The results are compared with the calculations carried out in the frames of the Glauber-Sitenko diffraction multiple scattering theory. The deviation of the calculated differential cross sections from the experimental ones is observed. In the region of the diffraction cone the deviation has a different sign for ap and aa scattering and amounts to 10-15%
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DIFFERENT VALUES FOR SIG CORRESPONDS TO DIFFERENT MODELS.
The energy dependence of the K L 0 -K S 0 transmission regeneration amplitudes on deuterons and neutrons in the momentum region 10–50 GeV/ c is determined. The moduli of the modified transmission amplitudes are momentum dependent. These dependences are fitted by the expression A j p − nj , where A j and n j ( j = d, n) are constants: A d =2.88 ±0.04 mb , n d =0.546±0.030, for deuterons , A n =1.97 ±0.14 mb , n n =0.530±0.019, for neutrons , The amplitude phases do not depend on the kaon momentum and are equal to ϕ d = (−130.9 ± 2.7)° ϕ n = (−132.3 ± 1.7)°. The mean value of the ratio of the total cross-section differences for K 0 and K 0 interactions with neutrons and protons is determined. The residues of the partial ω and ϱ amplitudes, which contribute to the kaon-nucleon interaction amplitudes, are also obtained.
FORWARD CROSS SECTION, AMPLITUDE AND PHASE FOR K0 REGENERATION.
(AK0 - K0) TOTAL CROSS SECTION DIFFERENCES.
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REAL/IMAG OF FORWARD AMPLITUDE FROM FIT TO D(SIG)/DT.
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THE AVERAGE PHASE IS -130.9 +- 2.7 DEG (NO EXPLICIT MOMENTUM DEPENDENCE). USING ABS(ETA+-) = 2.3*10**-3.
REGENERATION AMPLITUDE ASSUMING MOMENTUM INDEPENDENT CONSTANT PHASE.
CROSS SECTION DIFFERENCES ASSUMING MOMENTUM INDEPENDENT CONSTANT PHASE.
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