"Lys\u00E1k, Roman" . . . "Albrow, M. G." . . "US - Spojen\u00E9 st\u00E1ty americk\u00E9" . "7"^^ . . . "108" . . "000300576000006" . "RIV/68378271:_____/12:00388734!RIV13-AV0-68378271" . . "Observation of exclusive gamma gamma production in pp\u02C9 collisions at s=1.96 TeV" . . "We have observed exclusive gamma gamma production in proton-antiproton collisions at root s = 1.96 TeV, using data from 1.11 +/- 0.07 fb(-1) integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E-T > 2.5 GeV and pseudorapidity |eta| < 1.0, with no other particles detected in -7.4 < eta < +7.4. The two showers have similar ET and azimuthal angle separation Delta phi similar to pi; 34 events have two charged particle tracks, consistent with the QED process p<(p)over bar> --> p + e(+)e(-) + (p) over bar by two-photon exchange, while 43 events have no charged tracks. The number of these events that are exclusive pi(0)pi(0) is consistent with zero and is < 15 at 95% C. L. The cross section for p<(p)over bar> --> p + gamma gamma + (p) over bar with |eta(gamma)| < 1.0 and E-T(gamma) > 2.5 GeV is 2.48(-0.35)(+0.40)(stat)(-0.51)(+0.40)(syst) pb." . "1"^^ . "[7A32F6536511]" . "Lys\u00E1k, Roman" . . . "Physical Review Letters" . "10.1103/PhysRevLett.108.081801" . . . "P(LC527), Z(AV0Z10100502)" . "Aaltonen, T." . . "475"^^ . "0031-9007" . "Observation of exclusive gamma gamma production in pp\u02C9 collisions at s=1.96 TeV"@en . "8" . . "We have observed exclusive gamma gamma production in proton-antiproton collisions at root s = 1.96 TeV, using data from 1.11 +/- 0.07 fb(-1) integrated luminosity taken by the Run II Collider Detector at Fermilab. We selected events with two electromagnetic showers, each with transverse energy E-T > 2.5 GeV and pseudorapidity |eta| < 1.0, with no other particles detected in -7.4 < eta < +7.4. The two showers have similar ET and azimuthal angle separation Delta phi similar to pi; 34 events have two charged particle tracks, consistent with the QED process p<(p)over bar> --> p + e(+)e(-) + (p) over bar by two-photon exchange, while 43 events have no charged tracks. The number of these events that are exclusive pi(0)pi(0) is consistent with zero and is < 15 at 95% C. L. The cross section for p<(p)over bar> --> p + gamma gamma + (p) over bar with |eta(gamma)| < 1.0 and E-T(gamma) > 2.5 GeV is 2.48(-0.35)(+0.40)(stat)(-0.51)(+0.40)(syst) pb."@en . "electromagnetic showers; exchange two-photon; quantum electrodynamics; photon transverse energy; anti-p p exclusive reaction; rapidity; CDF"@en . . . "155529" . "Observation of exclusive gamma gamma production in pp\u02C9 collisions at s=1.96 TeV"@en . "RIV/68378271:_____/12:00388734" . "Observation of exclusive gamma gamma production in pp\u02C9 collisions at s=1.96 TeV" . . . "Gonzalez, B. A." . . . .