HEPData Search

A measurement of the total $pp$ cross section at the LHC at $\sqrt{s}=7$ TeV is presented. In a special run with high-$\beta^{\star}$ beam optics, an integrated luminosity of 80 $\mu$b$^{-1}$ was accumulated in order to measure the differential elastic cross section as a function of the Mandelstam momentum transfer variable $t$. The measurement is performed with the ALFA sub-detector of ATLAS. Using a fit to the differential elastic cross section in the $|t|$ range from 0.01 GeV$^2$ to 0.1 GeV$^2$ to extrapolate to $|t|\rightarrow 0$, the total cross section, $\sigma_{\mathrm{tot}}(pp\rightarrow X)$, is measured via the optical theorem to be: $$\sigma_{\mathrm{tot}}(pp\rightarrow X) = 95.35 \; \pm 0.38 \; ({\mbox{stat.}}) \pm 1.25 \; ({\mbox{exp.}}) \pm 0.37 \; (\mbox{extr.}) \; \mbox{mb},$$ where the first error is statistical, the second accounts for all experimental systematic uncertainties and the last is related to uncertainties in the extrapolation to $|t|\rightarrow 0$. In addition, the slope of the elastic cross section at small $|t|$ is determined to be $B = 19.73 \pm 0.14 \; ({\mbox{stat.}}) \pm 0.26 \; ({\mbox{syst.}}) \; \mbox{GeV}^{-2}$.

6 data tables match query

Table 1

The measured total cross section, the first systematic error accounts for all experimental uncertainties and the second error for the extrapolation t-->0.

Table 2

The nuclear slope of the differential eslastic cross section at small |t|, the first systematic error accounts for all experimental uncertainties and the second error for the extrapolation t-->0.

Table 3

The Optical Point dsigma/(elastic)/dt(t-->0), the total elastic cross section and the observed elastic cross section within the fiducial volume. The first systematic error accounts for all experimental uncertainties and the second error for the extrapolation t-->0.

Table 5

The measured differential elastic cross section. In addition to the statistical and total systematic uncertainties, the following 24 systematic shifts are given, which are included in the profile fit with their signs: -- Constraints: Beam optics uncertainty obtained by varying the ALFA constraints in the optics fit -- QScan: Variation by +/- 0.1 % of the quadrupole strength -- Q2: Fit of the strength of Q2 using the best value for the strength of Q1 and Q3 -- MadX: Uncertainty related to the beam transport replacing matrix transport by MadX PTC tracking -- Q5Q6: Variation of the strength of Q5 and Q6 by -0.2% as indicated by machine constraints -- Qmisal: Uncertainty due to the mis-alignment of the quadrupoles in the beam line -- Q1Q3: Propagation of the optics fit uncertainty in the strenght of Q1 and Q3 on the differential elastic cross section -- Stat2: Alignment uncertainty from the choice of a reference station -- Dist: Alignment uncertainty related to the distance calibration between the upper and lower detectors -- Leff: Alignment uncertainty related to effective lever arm used in the alignment optimization procedure -- Offv: Alignment uncertainty related to the vertical beam center offset -- Offh: Alignment uncertainty related to the horizontal beam center offset -- Ang: Alignment uncertainty related to the detector rotation in the x-y plane -- BGn: Uncertainty from the background normalization -- BGs: Uncertainty from the background shape -- MCres: Error from modelling of the detector response -- Slope: Residual dependence on the physics model estimated by varying the nuclear slope in the simulation by +/- 1 GeV^-2 -- Emit: Uncertainty from the emittance used to calculate beam divergence in the simulation -- Unf: Unfolding uncertainty from the data-driven closure test -- Trac: Uncertainty from the variation of the track reconstruction selection cuts -- Xing: Uncertainty from residual crossing angle in the horizontal plane -- Eff: Uncertainty from the reconstruction efficiency -- Lumi: Luminosity uncertainty (+/- 2.3%) -- Ebeam: Uncertainty from the nominal beam energy (+/- 0.65%) A small difference in the statistical uncertainties give here compared to the published version is related to insignificant rounding issues.

More…

rivet Analysis
Rapidity gap cross sections measured with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.

Eur.Phys.J.C 72 (2012) 1926, 2012.

Inspire Record 1084540 DOI 10.17182/hepdata.58497

Pseudorapidity gap distributions in proton-proton collisions at sqrt(s) = 7 TeV are studied using a minimum bias data sample with an integrated luminosity of 7.1 inverse microbarns. Cross sections are measured differentially in terms of Delta eta F, the larger of the pseudorapidity regions extending to the limits of the ATLAS sensitivity, at eta = +/- 4.9, in which no final state particles are produced above a transverse momentum threshold p_T Cut. The measurements span the region 0 < Delta eta F < 8 for 200 < p_T Cut < 800 MeV. At small Delta eta F, the data test the reliability of hadronisation models in describing rapidity and transverse momentum fluctuations in final state particle production. The measurements at larger gap sizes are dominated by contributions from the single diffractive dissociation process (pp -> Xp), enhanced by double dissociation (pp -> XY) where the invariant mass of the lighter of the two dissociation systems satisfies M_Y <~ 7 GeV. The resulting cross section is d sigma / d Delta eta F ~ 1 mb for Delta eta F >~ 3. The large rapidity gap data are used to constrain the value of the pomeron intercept appropriate to triple Regge models of soft diffraction. The cross section integrated over all gap sizes is compared with other LHC inelastic cross section measurements.

4 data tables match query

Table 1

The inelastic cross section differential in the forward rapidity gap size, DELTA(C=RAPGAP) for a maximum observed particle transverse momentum of 200 MeV in the gap.

Table 2

The inelastic cross section differential in the forward rapidity gap size, DELTA(C=RAPGAP) for a maximum observed particle transverse momentum of 400 MeV in the gap.

Table 3

The inelastic cross section differential in the forward rapidity gap size, DELTA(C=RAPGAP) for a maximum observed particle transverse momentum of 600 MeV in the gap.

More…

Date

Collaboration

Subject_areas

Phrases Reset

Reactions

Observables

CM Energies (GeV)

Authors Reset

STUDY OF DIFFRACTIVE PROCESSES IN EXCLUSIVE CHANNEL anti-p p ---> anti-p p (2 pi+) (2 pi-) AT 32-GeV/c

CROSS-SECTION OF PARTICLE DIFFRACTIVE PRODUCTION IN ANTI-P P INTERACTIONS AT 32-GEV/C. (IN RUSSIAN)

STUDY OF ELASTIC anti-p p SCATTERING AT 32-GeV/c

A Study of the Structure of the Events With the Multiparticle Diffraction Dissociation in $K^- p$ Exclusive Reactions at 32-{GeV}/$c$

K+ P AND K- P ELASTIC SCATTERING AT 32.1-GEV/C. FRANCE-SOVIET UNION AND CERN-SOVIET UNION COLLABORATIONS

Measurement of the total cross section from elastic scattering in $pp$ collisions at $\sqrt{s}=7$ TeV with the ATLAS detector

rivet Analysis
Rapidity gap cross sections measured with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV

Date

Collaboration

Subject_areas

Phrases Reset

Reactions

Observables

CM Energies (GeV)

Authors Reset

STUDY OF DIFFRACTIVE PROCESSES IN EXCLUSIVE CHANNEL anti-p p ---> anti-p p (2 pi+) (2 pi-) AT 32-GeV/c

CROSS-SECTION OF PARTICLE DIFFRACTIVE PRODUCTION IN ANTI-P P INTERACTIONS AT 32-GEV/C. (IN RUSSIAN)

STUDY OF ELASTIC anti-p p SCATTERING AT 32-GeV/c

A Study of the Structure of the Events With the Multiparticle Diffraction Dissociation in $K^- p$ Exclusive Reactions at 32-{GeV}/$c$

K+ P AND K- P ELASTIC SCATTERING AT 32.1-GEV/C. FRANCE-SOVIET UNION AND CERN-SOVIET UNION COLLABORATIONS

Measurement of the total cross section from elastic scattering in $pp$ collisions at $\sqrt{s}=7$ TeV with the ATLAS detector

rivet Analysis Rapidity gap cross sections measured with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV

rivet Analysis
Rapidity gap cross sections measured with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV