Bounds on the rise of total cross section from LHC7 and LHC8 data
| Autor: | Fagundes, D. A., Menon, M. J., Silva, P. V. R. G. |
|---|---|
| Rok vydání: | 2017 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1016/j.nuclphysa.2017.06.057 |
| Popis: | Recent measurements of the proton-proton total cross section $\sigma_{tot}$ at 7 and 8 TeV by the TOTEM and ATLAS Collaborations are characterized by some discrepant values: the TOTEM data suggest a rise of the cross section with the energy faster than the ATLAS data. Attempting to quantify these different behaviors, we develop new analytical fits to $\sigma_{tot}$ and $\rho$ data from $pp$ and $\bar{p}p$ scattering in the energy region 5 GeV - 8 TeV. The dataset comprises all the accelerator data below 7 TeV and we consider three ensembles by adding: either only the TOTEM data (T), or only the ATLAS data (A), or both sets (T+A). For the purposes, we use our previous RRPL$\gamma$ parametrization for $\sigma_{tot}(s)$, consisting of two Reggeons (RR), one critical Pomeron (P) and a leading log-raised-to-gamma (L$\gamma$) contribution (with $\gamma$ as a free fit parameter), analytically connected to $\rho(s)$ through singly-subtracted derivative dispersion relations and energy scale fixed at the physical threshold. The data reductions with ensembles T and A present good agreement with the experimental data analyzed and cannot be distinguished on statistical grounds. The quality of the fit is not as good with ensemble T+A. The fit results provide $\gamma \sim 2.3 \pm 0.1$ (T), $2.0 \pm 0.2$ (A), $2.1 \pm 0.2$ (T+A), with $\chi^2/\mathrm{DOF} \sim 1.07$ (T), $1.09$ (A), $1.14$ (T+A), suggesting extrema bounds for $\gamma$ given by 1.8 and 2.4. Fits with $\gamma = 2$ (fixed) are also developed and discussed. Comment: 14 pages, 3 figures, 6 tables, one appendix added (discussing some TOTEM data at 8 TeV), minor corrections, few comments added. Matches version accepted for publication in Nucl. Phys. A |
| Databáze: | arXiv |
| Externí odkaz: |
|