The coherent elastic reaction K + d → K + d and the break-up reaction K + d → K + pn are studied in a K + d experiment at 4.6 GeV/ c which the CERN 2 m bubble chamber. Partial and differential cross sections are given and the slopes of the differential cross sections are determined. The results for the reaction K + d → K + p(n s ), where n s denotes the spectator neutron, are compared with those of the reaction K + p → K + p on free protons. Combining our data with existing data on the reactions K + d → K 0 pp and K + p → K + p, parameters of the elastic K + -nucleon scattering at 4.6 GeV/ c are determined in the framework of the Glauber model. The D-wave of the deuteron and spin-flip effects are taken into account.
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Results are presented on the topological cross sections obtained for antiproton-proton interactions from an exposure of the Fermilab 30-inch bubble chamber to a 100 GeV/ c negative beam enriched in p 's. The p p inelastic cross section is found to be σ inel = 34.6 ± 0.4 mb, and the average inelastic charged particle multiplicity to be 〈 n 〉 = 6.74 ± 0.05.
ERRORS ARE STATISTICAL ONLY EXCEPT FOR 2-PRONG CROSS-SECTIONS.
EXPONENTIAL FIT TO ELASTIC T DISTRIBUTION TO CORRECT FOR AN APPARENT LOSS OF EVENTS AT SMALL -T.
Exclusive photoproduction of $\rho^0(770)$ mesons is studied using the H1 detector at the $ep$ collider HERA. A sample of about 900000 events is used to measure single- and double-differential cross sections for the reaction $\gamma p \to \pi^{+}\pi^{-}Y$. Reactions where the proton stays intact (${m_Y{=}m_p}$) are statistically separated from those where the proton dissociates to a low-mass hadronic system ($m_p{<}m_Y{<}10$ GeV). The double-differential cross sections are measured as a function of the invariant mass $m_{\pi\pi}$ of the decay pions and the squared $4$-momentum transfer $t$ at the proton vertex. The measurements are presented in various bins of the photon-proton collision energy $W_{\gamma p}$. The phase space restrictions are $0.5 < m_{\pi\pi} < 2.2$ GeV, ${\vert t\vert < 1.5}$ GeV${}^2$, and ${20 < W_{\gamma p} < 80}$ GeV. Cross section measurements are presented for both elastic and proton-dissociative scattering. The observed cross section dependencies are described by analytic functions. Parametrising the $m_{\pi\pi}$ dependence with resonant and non-resonant contributions added at the amplitude level leads to a measurement of the $\rho^{0}(770)$ meson mass and width at $m_\rho = 770.8\ {}^{+2.6}_{-2.7}$ (tot) MeV and $\Gamma_\rho = 151.3\ {}^{+2.7}_{-3.6}$ (tot) MeV, respectively. The model is used to extract the $\rho^0(770)$ contribution to the $\pi^{+}\pi^{-}$ cross sections and measure it as a function of $t$ and $W_{\gamma p}$. In a Regge asymptotic limit in which one Regge trajectory $\alpha(t)$ dominates, the intercept $\alpha(t{=}0) = 1.0654\ {}^{+0.0098}_{-0.0067}$ (tot) and the slope $\alpha^\prime(t{=}0) = 0.233\ {}^{+0.067 }_{-0.074 }$ (tot) GeV${}^{-2}$ of the $t$ dependence are extracted for the case $m_Y{=}m_p$.
Elastic ($m_Y=m_p$) and proton-dissociative ($1<m_Y<10$ GeV) $\pi^{+}\pi^{-}$ photoproduction off protons, differential in the dipion mass. The tabulated cross sections are $\gamma p$ cross sections but can be converted to $ep$ cross sections using the effective photon flux $\Phi_{\gamma/e}$.
Elastic ($m_Y=m_p$) and proton-dissociative ($1<m_Y<10$ GeV) $\pi^{+}\pi^{-}$ photoproduction off protons, differential in the dipion mass --- statistical correlations coefficients $\rho_{ij}$ only. Only one half of the (symmetric) matrix is stored. Bins are identified by their global bin number.
Fit of elastic ($m_Y=m_p$) and proton-dissociative ($1<m_Y<10$ GeV) $\pi^{+}\pi^{-}$ photoproduction cross section off protons with a Soeding-inspired analytic function including $\rho$ and $\omega$ meson resonant contributions as well as a continuum background which interfere at the amplitude level. Parameters with subscript "el" and "pd" correspond to elastic and proton-dissociative cross sections, respectively.
The angular distribution of π + p elastic scattering has been measured at an incident momentum of 10 GeV/ c . Nearly the whole angular range was covered in one experimental set-up. The pronounced dip at − t = 2.8 (GeV/ c ) 2 , observed at lower momenta, has diminished and is essentially a shoulder at 10 GeV/ c . The other structure at larger momentum transfers are also different in detail from what we observed at 5 GeV/ c . In the 90° c.m. region the differential cross-section is approximately one nb/(GeV/ c ) 2 , which is more than two orders of magnitude lower than at 5 GeV/ c .
THESE DATA ARE REPORTED MORE FULLY IN C. BAGLIN ET AL., NP B98, 365 (1975).
Angular distributions of π + and K + p elastic scattering have been measured for an incident beam momentum of 10.0 GeV/ c . For π + p elastic scattering almost the complete angular distribution was measured. The angular distribution of proton-proton elastic scattering was measured for an incident momentum of 9.0 GeV/ c in the interval of the four-momentum transfer squared from 0.7 (GeV/ c ) 2 to 5.0 (GeV/ v ) 2 . For π + p elastic scattering the structures at − t = 2.8 (GeV/ c ) 2 and − t = 4.8 (GeV/ c ) 2 are less pronounced than at lower momenta. The cross section for scattering at 90° in the c.m. system is of the order of 1 nb/GeV/ c ) 2 . For K + p elastic scattering is a break in the angular distribution around − t = 3 (GeV/ c ) 2 . The differential cross sections for proton-proton elastic scattering decrease smoothly with increasing momentum transfers.
S=19.667 GEV**2, U=-T-17.867 GEV**2.
S=19.91 GEV**2, U=-T-17.704 GEV**2.
S=18.74 GEV**2.
We present results of the total cross section differenceΔσТ obtained in transmission measurements at the energies 0.86, 0.88, 0.91 and 0.94 GeV. The SATURNE II polarized beam of free neutrons obtained from the break-up of polarized deuterons was transmitted through the polarized Saclay frozen-spin proton target. The beam and target polarizations were oriented in the vertical direction. The present results agree with previous SATURNE measurements and improve the amplitude analysis in the forward direction.
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Average of this result and data from Fontaine et al. 1991, Nucl.Phys. B358, 297 (<a href=http://durpdg.dur.ac.uk/scripts/reacsearch.csh/TESTREAC/red+2233> RED = 2233 </a>).
Final results for total cross section differences Δσ T and Δσ L measured with a polarized neutron beam transmitted through a polarized proton target are presented. Measurements were carried out at SATURNE II, at 11 energies between 0.63 and 1.1 GeV for Δσ T and at 9 energies between 0.312 and 1.1 GeV for Δσ L . The results are compared with measurements at PSI and LAMPF as well as with Δσ L data points deduced from p-d and p-p transmission experiments at the ANL-ZGS. The present results together with the corresponding pp data allow to determine two of the three imaginary parts of forward scattering amplitudes for isospin I = 0.
Measurements of the tranverse cross section differences.
Measurements of the tranverse cross section differences.
Measurement of the longitudinal cross section difference.
The cross section for the diffractive deep-inelastic scattering process $ep \to e X p$ is measured, with the leading final state proton detected in the H1 Forward Proton Spectrometer. The data analysed cover the range \xpom <0.1 in fractional proton longitudinal momentum loss, 0.08 < |t| < 0.5 GeV^{-2} in squared four-momentum transfer at the proton vertex, 2 < Q^2 < 50 GeV^2 in photon virtuality and 0.004 < \beta = x / \xpom < 1, where x is the Bjorken scaling variable. For $\xpom \lapprox 10^{-2}$, the differential cross section has a dependence of approximately ${\rm d} \sigma / {\rm d} t \propto e^{6 t}$, independently of \xpom, \beta and Q^2 within uncertainties. The cross section is also measured triple differentially in \xpom, \beta and Q^2. The \xpom dependence is interpreted in terms of an effective pomeron trajectory with intercept $\alpha_{\pom}(0)=1.114 \pm 0.018 ({\rm stat.}) \pm 0.012 ({\rm syst.}) ^{+0.040}_{-0.020} ({\rm model})$ and a sub-leading exchange. The data are in good agreement with an H1 measurement for which the event selection is based on a large gap in the rapidity distribution of the final state hadrons, after accounting for proton dissociation contributions in the latter. Within uncertainties, the dependence of the cross section on x and Q^2 can thus be factorised from the dependences on all studied variables which characterise the proton vertex, for both the pomeron and the sub-leading exchange.
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In a special run of the LHC with $\beta^\star = 2.5~$km, proton-proton elastic-scattering events were recorded at $\sqrt{s} = 13~$TeV with an integrated luminosity of $340~\mu \textrm{b}^{-1}$ using the ALFA subdetector of ATLAS in 2016. The elastic cross section was measured differentially in the Mandelstam $t$ variable in the range from $-t = 2.5 \cdot 10^{-4}~$GeV$^{2}$ to $-t = 0.46~$GeV$^{2}$ using 6.9 million elastic-scattering candidates. This paper presents measurements of the total cross section $\sigma_{\textrm{tot}}$, parameters of the nuclear slope, and the $\rho$-parameter defined as the ratio of the real part to the imaginary part of the elastic-scattering amplitude in the limit $t \rightarrow 0$. These parameters are determined from a fit to the differential elastic cross section using the optical theorem and different parameterizations of the $t$-dependence. The results for $\sigma_{\textrm{tot}}$ and $\rho$ are \begin{equation*} \sigma_{\textrm{tot}}(pp\rightarrow X) = \mbox{104.7} \pm 1.1 \; \mbox{mb} , \; \; \; \rho = \mbox{0.098} \pm 0.011 . \end{equation*} The uncertainty in $\sigma_{\textrm{tot}}$ is dominated by the luminosity measurement, and in $\rho$ by imperfect knowledge of the detector alignment and by modelling of the nuclear amplitude.
The measured total cross section. The systematic uncertainty includes experimental and theoretical uncerainties.
The rho-parameter, i.e. the ratio of the real to imaginary part of the elastic scattering amplitude extrapolated to t=0. The systematic uncertainty includes experimental and theoretical uncerainties.
The nuclear slope parameter B from a fit of the form exp(-Bt-Ct^2-Dt^3). The systematic uncertainty includes experimental and theoretical uncerainties.
The differential cross section for neutron-proton elastic scattering was measured in the diffraction region with incident-neutron momenta between 8 and 30 GeV/c. The experiment was a spark-chamber-counter experiment, conducted at the alternating-gradient synchrotron. Results are presented and compared with currently available lower energy np data and comparable energy pp data.
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