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Measurement of Elastic pp Scattering at $\sqrt{s}$ = 8 TeV in the Coulomb-Nuclear Interference Region - Determination of the $\rho$-Parameter and the Total Cross-Section

The TOTEM collaboration Antchev, G. ; Aspell, P. ; Atanassov, I. ; et al.

Eur.Phys.J.C 76 (2016) 661, 2016.

Inspire Record 1489188 DOI 10.17182/hepdata.127946

The TOTEM experiment at the CERN LHC has measured elastic proton-proton scattering at the centre-of-mass energy $\sqrt{s}$ = 8 TeV and four-momentum transfers squared, |t|, from 6 x $10^{-4}$ GeV$^2$ to 0.2 GeV$^2$. Near the lower end of the |t|-interval the differential cross-section is sensitive to the interference between the hadronic and the electromagnetic scattering amplitudes. This article presents the elastic cross-section measurement and the constraints it imposes on the functional forms of the modulus and phase of the hadronic elastic amplitude. The data exclude the traditional Simplified West and Yennie interference formula that requires a constant phase and a purely exponential modulus of the hadronic amplitude. For parametrisations of the hadronic modulus with second- or third-order polynomials in the exponent, the data are compatible with hadronic phase functions giving either central or peripheral behaviour in the impact parameter picture of elastic scattering. In both cases, the $\rho$-parameter is found to be 0.12 $\pm$ 0.03. The results for the total hadronic cross-section are $\sigma_{tot}$ = (102.9 $\pm$ 2.3) mb and (103.0 $\pm$ 2.3) mb for central and peripheral phase formulations, respectively. Both are consistent with previous TOTEM measurements.

1 data table

Table 1

Differential cross-section.

Measurement of the total cross section from elastic scattering in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.

Phys.Lett.B 761 (2016) 158-178, 2016.

Inspire Record 1477585 DOI 10.17182/hepdata.73997

A measurement of the total $pp$ cross section at the LHC at $\sqrt{s}=8$ TeV is presented. An integrated luminosity of $500$ $\mu$b$^{-1}$ was accumulated in a special run with high-$\beta^{\star}$ beam optics 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 $0.014$ GeV$^2$ to $0.1$ GeV$^2$ to extrapolate $t\rightarrow 0$, the total cross section, $\sigma_{\mathrm{tot}}(pp\rightarrow X)$, is measured via the optical theorem to be: $\sigma_{\mathrm{tot}}(pp\rightarrow X) = {96.07} \; \pm 0.18 \; ({{stat.}}) \pm 0.85 \; ({{exp.}}) \pm 0.31 \; ({extr.}) \; {mb} \;,$ where the first error is statistical, the second accounts for all experimental systematic uncertainties and the last is related to uncertainties in the extrapolation $t\rightarrow 0$. In addition, the slope of the exponential function describing the elastic cross section at small $t$ is determined to be $B = 19.74 \pm 0.05 \; ({{stat.}}) \pm 0.23 \; ({{syst.}}) \; {GeV}^{-2}$.

6 data tables

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 total elastic cross section and the observed elastic cross section within the fiducial volume.

Table 5

The measured differential elastic cross section. In addition to the statistical and total systematic uncertainties, the following 22 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 -- Q5Q6: Variation of the strength of Q5 and Q6 by -0.2% as indicated by machine constraints -- MadX: Uncertainty related to the beam transport replacing matrix transport by MadX PTC tracking -- 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 -- Aopt: Alignment uncertainty from the 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 (+/- 1.5%) -- Ebeam: Uncertainty from the nominal beam energy (+/- 0.65%) Small differences in the values given here compared to the published version are related to insignificant rounding issues.

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Forward peak in $\pi^+$ photoproduction

Buschhorn, G. ; Heide, P. ; Kötz, U. ; et al.

Phys.Lett.B 25 (1967) 622-623, 1967.

Inspire Record 1392927 DOI 10.17182/hepdata.29549

The π+—photoproduction cross section is found to have a peak in the forward direction in disagreement with simple Regge pole models.

1 data table

Table 1

No description provided.

Measurement of the reactions $K^+ d\to K^+ d$ and $K^+ d \to p^+ p n$ and an investigation of elastic $K^+$-nucleon scattering at 4.6 GeV/ c

Dehm, G. ; Geist, W. ; Göbel, G. ; et al.

Nucl.Phys.B 93 (1975) 387-404, 1975.

Inspire Record 1392684 DOI 10.17182/hepdata.26096

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.

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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$K^- p$ elastic scattering at 10 GeV/c

The Aachen-Berlin-CERN-London (I.C.)-Vienna collaboration Aderholz, M. ; Bartsch, J. ; Keppel, E. ; et al.

Phys.Lett.B 24 (1967) 434-437, 1967.

Inspire Record 1392680 DOI 10.17182/hepdata.29583

K − p elastic scattering at 10 GeV/ c is studied on ∼3600 bubble chamber events. The elastic cross section is found to be σ el = (3.20 ± 0.14)mb and the ratio σ el σ tot = (0.142 ± 0.006) , that is below the upper limit of 0.185 suggested in a model by Van Hove. The value of the forward differential cross section is consistent with zero real part to the scattering amplitude. The slope of d σ d t is similar to that for π ± and greater than that of K + , with no evidence for shrinkage of the diffraction peak. No events of backward scattering were observed. The Regge-pole model of Phillips and Rarita gives a good fit to the data.

1 data table

Table 1

No description provided.

Proton-proton small angle scattering and total cross section of 10.0 GeV⧸c

Bellettini, G. ; Cocconi, G. ; Diddens, A.N. ; et al.

Phys.Lett. 19 (1966) 705-705, 1966.

Inspire Record 1389783 DOI 10.17182/hepdata.782

None

3 data tables

Table 1

No description provided.

Table 2

Axis error includes +- 0.0/0.0 contribution.

Table 3

No description provided.

$K^+ n$ charge exchange reaction at 3 GeV/c

Goldschmidt-Clermont, Y. ; Henri, V.P. ; Jongejans, B. ; et al.

Phys.Lett.B 27 (1968) 602-604, 1968.

Inspire Record 1389631 DOI 10.17182/hepdata.29205

About 100 000 pictures, with an average of ∼12K + per picture, taken in the 81 cm Saclay deuterium bubble chamber exposed to a separated 3 GeV/c K + beam have been analysed for the reaction K + d→K 0 pp in the 1-prong V 0 and 2-prong V 0 topologies. 214 such events have been found allowing a determination of the differential cross-section. A comparison with the prediction of Rarita and Schwarzschild yields reasonable agreement; in particular a large real part is inferred for the amplitude for the reaction K + n→K 0 p.

2 data tables

Table 1

The errors are statistical only.

Table 2

The errors are statistical only. To evaluate the cross section on neutron thE data are divided on (1-FORMFACTOR(C=DEUT). For definition of the formfactor see L. Durand, Phys. Rev. 115 (1959) 1020.