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The total neutron cross-sections were measured with high precision for hydrogen and deuterium. At an average neutron momentum of 10 GeV/c we obtained σ T (np)=39.5±0.5 mb and σ T (nd)=73.3±1.1 mb. These values are in excellent agreement with p-p and p-d total cross sections. No energy dependence was found for n-p cross section between 4 and 10 GeV/c.
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The production of $\Upsilon$ mesons in $pp$ collisions at $\sqrt=7$ and $8\,\mathrm{TeV}$ is studied with the LHCb detector using data samples corresponding to an integrated luminosity of $1\,\mathrm{fb}^{-1}$ and $2\,\mathrm{fb}^{-1}$ respectively. The production cross-sections and ratios of cross-sections are measured as functions of the meson transverse momentum $p_T$ and rapidity $y$, for $p_T<30\,\mathrm{GeV}/c$} and $2.0<y<4.5$.
Double-differential cross-section $\mathrm{d}^2 \sigma ( pp \to ( \Upsilon \to \mu^+ \mu^- ) X ) / \mathrm{d} p_T/\mathrm{d}y$ [pb/(GeV/$c$)] for $2.0 < y < 2.5$.
Double-differential cross-section $\mathrm{d}^2 \sigma ( pp \to ( \Upsilon \to \mu^+ \mu^- ) X ) / \mathrm{d} p_T/\mathrm{d}y$ [pb/(GeV/$c$)] for $2.0 < y < 2.5$.
Double-differential cross-section $\mathrm{d}^2 \sigma ( pp \to ( \Upsilon \to \mu^+ \mu^- ) X ) / \mathrm{d} p_T/\mathrm{d}y$ [pb/(GeV/$c$)].
Using the internal beam of DESY elastic electron-proton cross-sections were measured at various angles between 32° and 130°, and with momentum transfers ofq 2=39, 60, 80 and 110 fm−2. Two single-quadrupole spectrometers, movable around a common liquid-hydrogen target, were used for analysing the momentum of the scattered electrons. Čerenkov and shower counters discriminated against pion and low-energy background. As a cross-section reference, recoil protons from elastic scattering atq 2=10 fm−2 were used, with a quantameter serving as an intermediate monitor. The data are consistent with the Rosenbluth formula, giving real form factorsG E andG M . Both continue to decrease with increasing momentum transfer, but somewhat faster than indicated by measurements performed so far.
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A measurement of the production cross-section for $Z$ bosons that decay to muons is presented. The data were recorded by the LHCb detector during $pp$ collisions at a centre-of-mass energy of 7 TeV, and correspond to an integrated luminosity of 1.0 fb$^{-1}$. The cross-section is measured for muons in the pseudorapidity range $2.0 < \eta < 4.5$ with transverse momenta $p_{T} > 20$ GeV/c. The dimuon mass is restricted to $60 < M_{\mu^{+}\mu^{-}} < 120$ GeV/c$^{2}$. The measured cross-section is $$\sigma_{Z\rightarrow\mu^{+}\mu^{-}} = (76.0 \pm 0.3 \pm 0.5 \pm 1.0 \pm 1.3) \, \text{pb}$$ where the uncertainties are due to the sample size, systematic effects, the beam energy and the luminosity. This result is in good agreement with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. The cross-section is also measured differentially as a function of kinematic variables of the $Z$ boson. Ratios of the production cross-sections of electroweak bosons are presented using updated LHCb measurements of $W$ boson production. A precise test of the Standard Model is provided by the measurement of the ratio $$\frac{\sigma_{W^{+}\rightarrow\mu^{+}\nu_{\mu}} + \sigma_{W^{-}\rightarrow\mu^{-}\bar{\nu}_{\mu}}}{\sigma_{Z\rightarrow\mu^{+}\mu^{-}}} = 20.63\pm0.09\pm0.12\pm0.05,$$ where the uncertainty due to luminosity cancels.
Inclusive cross-section for $Z$ boson production in bins of rapidity. The uncertainties are statistical, systematic, beam and luminosity.
Inclusive cross-section for $Z$ boson production in bins of transverse momentum. The uncertainties are statistical, systematic, beam and luminosity.
Inclusive cross-section for $Z$ boson production in bins of PHI*. The uncertainties are statistical, systematic, beam and luminosity.
The differential cross sections for neutron-proton charge-exchange scattering have been measured with high statistics in the region of momentum transfer squared 0.002 < | t | ⩽ 0.400 (GeV/ c ) 2 and for incident neutron momenta 9 < p ⩽ 23 GeV/ c .
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The differential cross sections for neutron-proton elastic charge-exchange scattering have been measured with a two-arm technique for incident neutron momenta between 22 and 65 GeV/ c and for values of the momentum transfer squared between 0.002 and 0.8 (GeV/ c ) 2 . The sharp forward peak observed previously at lower energies is also present at momenta up to 65 GeV/ c ; however the s dependence of the cross section is slowing down.
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The neutron-proton elastic differential cross section has been measured for incident momenta between 10 and 70 GeV/c and for values of the momentum transfer squared between 0.1 and 2.8 (GeV/c) 2 . The forward peak and the break at about ∣ t ∣ = 1 (GeV/ c ) 2 are very similar to corresponding pp data.
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Neutron-proton total cross-sections were measured in the momentum range from 8 GeV/ c to 21 GeV/ c with an accuracy of better than 2% using a 0 o neutron beam at the CERN Proton Synchrotron. The np total cross-section drops from 39.7 mb at 8 GeV/ c at 21 GeV/ c , and thus follows closely the pp total cross-sections in this momentum interval.
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