Evidence for $$\text {W}\text {W}$$ production from double-parton interactions in proton–proton collisions at $$\sqrt{s} = 13 \,\text {TeV} $$
A. M. Sirunyan, A. Tumasyan, W. Adam, F. Ambrogi, T. Bergauer, J. Brandstetter, M. Dragicevic, J. Erö, A. Escalante Del Valle, M. Flechl, R. Frühwirth, M. Jeitler, Natascha Krammer, I. Krätschmer, D. Liko, T. Madlener, I. Mikulec, N. Rad, J. Schieck, R. Schöfbeck, M. Spanring, D. Spitzbart, W. Waltenberger, C.-E. Wulz, M. Zarucki, V. Drugakov, V. Mossolov, J. Suarez Gonzalez, M. R. Darwish, E. Wolf, D. Di Croce, X. Janssen, J. Lauwers, A. Lelek, M. Pieters, H. Rejeb Sfar, H. Van Haevermaet, P. Van Mechelen, S. Van Putte, N. Van Remortel, F. Blekman, E. S. Bols, S. S. Chhibra, J. D’Hondt, J. De Clercq, D. Lontkovskyi, S. Lowette, I. Marchesini, S. Moortgat, L. Moreels, Q. Python, K. Skovpen, S. Tavernier, W. Van Doninck, P. Van Mulders, I. Van Parijs, D. Beghin, B. Bilin, H. Brun, B. Clerbaux, G. De Lentdecker, H. Delannoy, B. Dorney, L. Favart, A. Grebenyuk, A. K. Kalsi, J. Luetic, A. Popov, N. Postiau, E. Starling, L. Thomas, C. Vander Velde, P. Vanlaer, D. Vannerom, T. Cornelis, D. Dobur, I. Khvastunov, C. Roskas, D. Trocino, M. Tytgat, W. Verbeke, B. Vermassen, Martina Vit, N. Zaganidis, Olivier Bondu, G. Bruno, C. Caputo, P. David, C. Delaere, M. Delcourt, A. Giammanco, V. Lemaı̂tre, A. Magitteri, J. Prisciandaro, A. Saggio, M. Vidal Marono, P. Vischia, J. Zobec, F. L. Alves, G. A. Alves
Abstract
Abstract A search for $$\text {W}\text {W}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>WW</mml:mtext></mml:math> production from double-parton scattering processes using same-charge electron-muon and dimuon events is reported, based on proton-proton collision data collected at a center-of-mass energy of $$13\,\text {TeV} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>13</mml:mn><mml:mspace/><mml:mtext>TeV</mml:mtext></mml:mrow></mml:math> . The analyzed data set corresponds to an integrated luminosity of $$77.4{\,\text {fb}^{-1}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>77.4</mml:mn><mml:mrow><mml:mspace/><mml:msup><mml:mtext>fb</mml:mtext><mml:mrow><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:mrow></mml:math> , collected using the CMS detector at the LHC in 2016 and 2017. Multivariate classifiers are used to discriminate between the signal and the dominant background processes. A maximum likelihood fit is performed to extract the signal cross section. This leads to the first evidence for $$\text {W}\text {W}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mtext>WW</mml:mtext></mml:math> production via double-parton scattering, with a significance of 3.9 standard deviations. The measured inclusive cross section is $$1.41\pm 0.28\,\text {(stat)} \pm 0.28\,\text {(syst)} \,\text {pb} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>1.41</mml:mn><mml:mo>±</mml:mo><mml:mn>0.28</mml:mn><mml:mspace/><mml:mtext>(stat)</mml:mtext><mml:mo>±</mml:mo><mml:mn>0.28</mml:mn><mml:mspace/><mml:mtext>(syst)</mml:mtext><mml:mspace/><mml:mtext>pb</mml:mtext></mml:mrow></mml:math> .