Search for high-mass exclusive diphoton production with tagged protons in proton-proton collisions at s=13 TeV

Abstract

A search is presented for high-mass exclusive diphoton production via photon-photon fusion in proton-proton collisions at <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msqrt><a:mi>s</a:mi></a:msqrt><a:mo>=</a:mo><a:mn>13</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>TeV</a:mi></a:math> in events where both protons survive the interaction. The analysis utilizes data corresponding to an integrated luminosity of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mn>103</c:mn><c:mtext> </c:mtext><c:mtext> </c:mtext><c:msup><c:mi>fb</c:mi><c:mrow><c:mo>−</c:mo><c:mn>1</c:mn></c:mrow></c:msup></c:math> collected in 2016–2018 with the central CMS detector and the CMS and TOTEM precision proton spectrometer (PPS). Events that have two photons with high transverse momenta (<e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:msubsup><e:mrow><e:mi>p</e:mi></e:mrow><e:mrow><e:mi mathvariant="normal">T</e:mi></e:mrow><e:mrow><e:mi>γ</e:mi></e:mrow></e:msubsup></e:mrow><e:mo>&gt;</e:mo><e:mn>100</e:mn><e:mtext> </e:mtext><e:mtext> </e:mtext><e:mi>GeV</e:mi></e:math>), back-to-back in azimuth, and with a large diphoton invariant mass (<h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline"><h:msub><h:mi>m</h:mi><h:mrow><h:mi>γ</h:mi><h:mi>γ</h:mi></h:mrow></h:msub><h:mo>&gt;</h:mo><h:mn>350</h:mn><h:mtext> </h:mtext><h:mtext> </h:mtext><h:mi>GeV</h:mi></h:math>) are selected. To remove the dominant inclusive diphoton backgrounds, the kinematic properties of the protons detected in PPS are required to match those of the central diphoton system. Only events having opposite-side forward protons detected with a fractional momentum loss between 0.035 and 0.15 (0.18) for the detectors on the negative (positive) side of CMS are considered. One exclusive diphoton candidate is observed for an expected background of 1.1 events. Limits at 95% confidence level are derived for the four-photon anomalous coupling parameters <j:math xmlns:j="http://www.w3.org/1998/Math/MathML" display="inline"><j:mrow><j:mo stretchy="false">|</j:mo><j:msub><j:mi>ζ</j:mi><j:mn>1</j:mn></j:msub><j:mo stretchy="false">|</j:mo></j:mrow><j:mo>&lt;</j:mo><j:mn>0.073</j:mn><j:mtext> </j:mtext><j:mtext> </j:mtext><j:msup><j:mi>TeV</j:mi><j:mrow><j:mo>−</j:mo><j:mn>4</j:mn></j:mrow></j:msup></j:math> and <n:math xmlns:n="http://www.w3.org/1998/Math/MathML" display="inline"><n:mrow><n:mo stretchy="false">|</n:mo><n:msub><n:mi>ζ</n:mi><n:mn>2</n:mn></n:msub><n:mo stretchy="false">|</n:mo></n:mrow><n:mo>&lt;</n:mo><n:mn>0.15</n:mn><n:mtext> </n:mtext><n:mtext> </n:mtext><n:msup><n:mi>TeV</n:mi><n:mrow><n:mo>−</n:mo><n:mn>4</n:mn></n:mrow></n:msup></n:math>, using an effective field theory. Additionally, upper limits are placed on the production of axionlike particles with coupling strength to photons <r:math xmlns:r="http://www.w3.org/1998/Math/MathML" display="inline"><r:msup><r:mi>f</r:mi><r:mrow><r:mo>−</r:mo><r:mn>1</r:mn></r:mrow></r:msup></r:math> that varies from <t:math xmlns:t="http://www.w3.org/1998/Math/MathML" display="inline"><t:mn>0.03</t:mn><t:mtext> </t:mtext><t:mtext> </t:mtext><t:msup><t:mi>TeV</t:mi><t:mrow><t:mo>−</t:mo><t:mn>1</t:mn></t:mrow></t:msup></t:math> to <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"><v:mn>1</v:mn><v:mtext> </v:mtext><v:mtext> </v:mtext><v:msup><v:mi>TeV</v:mi><v:mrow><v:mo>−</v:mo><v:mn>1</v:mn></v:mrow></v:msup></v:math> over the mass range from 500 to 2000 GeV. © 2024 CERN, for the CMS and TOTEMs Collaboration 2024 CERN