Searching for New Physics with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"><mml:mi>b</mml:mi><mml:mover accent="true"><mml:mrow><mml:mi>b</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover><mml:msup><mml:mrow><mml:mi>ℓ</mml:mi></mml:mrow><mml:mrow><mml:mo linebreak="badbreak" linebreakstyle="after">+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>ℓ</mml:mi></mml:mrow><mml:mrow><mml:mo linebreak="badbreak" linebreakstyle="after">−</mml:mo></mml:mrow></mml:msup></mml:math> contact interactions

We study the impact of contact interactions involving two leptons (electrons or muons) and two b-quarks (bb¯ℓ+ℓ−) on the high-mass di-lepton region at the LHC. We consider different selections of b-tagged jet multiplicities in the di-lepton final states: inclusive (no selection), 0, 1 and 2 b-tagged jets, and show that the single b-jet selection significantly improves the sensitivity to New Physics (NP) in the form of the bb¯ℓ+ℓ− contact term. We obtain a better sensitivity compared to the currently existing searches of NP in the di-lepton inclusive channel. In particular, the expected limits go beyond competitive bounds set by LEP (for electrons) on the scale of NP, Λ, by a factor of 1.2−3.1, depending on the chirality structure of the operator. In addition, the expected limits on Λ, set by using a non-resonant LHC di-lepton inclusive search, are expected to be improved by a factor of 1.3−1.4 for both electrons and muons.

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