Highly boosted dielectron identification in proton-proton collisions at; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline">; <mml:msqrt>; <mml:mi>s</mml:mi>; </mml:msqrt>; <mml:mo>=</mml:mo>; <mml:mn>13</mml:mn>; <mml:mtext> </mml:mtext>; <mml:mtext> </mml:mtext>; <mml:mi>TeV</mml:mi>; </mml:math> | CU Experts

; A new technique is developed to identify dielectrons (; ; ; ; e; +; ; ; e; −; ; ; ; ) with Lorentz boost; ; ; γ; L; ; >; 20; ; that produce one single merged cluster in the electromagnetic calorimeter of the CMS detector. The identification uses two multivariate models: one for the case where both electron tracks are reconstructed, and another where only one of the tracks is reconstructed. The efficiency is determined using proton-proton collision data collected at a center-of-mass energy of 13 TeV. Boosted; ; J; /; ψ; ; mesons decaying into; ; ; ; ; e; ; ; +; ; ; ; ; e; ; ; −; ; ; ; ; pairs are used to estimate the efficiency of the model with two tracks, yielding an overall efficiency of 80%. The; ; Z; →; ; μ; +; ; ; μ; −; ; γ; ; events, where the photon converts into a collimated dielectron, are used for the model with a single track, yielding an efficiency of about 60%. A dedicated energy correction for dielectron candidates is also developed using; ; ; B; ±; ; →; ; J; /; ψ; ; ; K; ±; ; →; ; e; +; ; ; e; −; ; ; K; ±; ; ; data.;

Hayrapetyan A; Makarenko V; Tumasyan A; Adam W; Andrejkovic JW; Benato L; Bergauer T; Dragicevic M; Giordano C; Hussain PS

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