Probing lepton flavor violation in meson decays with LHC data

Abstract

Abstract In this letter, we use LHC data from the Drell–Yan processes $$pp\rightarrow \ell _i\ell _j$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>p</mml:mi> <mml:mi>p</mml:mi> <mml:mo>→</mml:mo> <mml:msub> <mml:mi>ℓ</mml:mi> <mml:mi>i</mml:mi> </mml:msub> <mml:msub> <mml:mi>ℓ</mml:mi> <mml:mi>j</mml:mi> </mml:msub> </mml:mrow> </mml:math> (with $$i\ne j$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>i</mml:mi> <mml:mo>≠</mml:mo> <mml:mi>j</mml:mi> </mml:mrow> </mml:math> ) to derive model-independent upper limits on lepton-flavor-violating meson decays. Our analysis is based on an Effective Field Theory (EFT) approach and it does not require a specific assumption regarding the basis of effective operators. We find that current LHC data (140 $$\textrm{fb}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mtext>fb</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> ) already provides competitive limits on $${\mathcal {B}}(B\rightarrow \pi e \tau )$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>B</mml:mi> <mml:mo>(</mml:mo> <mml:mi>B</mml:mi> <mml:mo>→</mml:mo> <mml:mi>π</mml:mi> <mml:mi>e</mml:mi> <mml:mi>τ</mml:mi> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> and $${\mathcal {B}}(B\rightarrow \pi \mu \tau )$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>B</mml:mi> <mml:mo>(</mml:mo> <mml:mi>B</mml:mi> <mml:mo>→</mml:mo> <mml:mi>π</mml:mi> <mml:mi>μ</mml:mi> <mml:mi>τ</mml:mi> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> with respect to the ones obtained through experimental searches at the B -factories. Moreover, we derive upper limits on several decays that have not been searched for experimentally yet, such as $$D^0\rightarrow e\tau $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>D</mml:mi> <mml:mn>0</mml:mn> </mml:msup> <mml:mo>→</mml:mo> <mml:mi>e</mml:mi> <mml:mi>τ</mml:mi> </mml:mrow> </mml:math> in the charm sector, and various semileptonic decays such as $$B\rightarrow \rho \mu \tau $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>B</mml:mi> <mml:mo>→</mml:mo> <mml:mi>ρ</mml:mi> <mml:mi>μ</mml:mi> <mml:mi>τ</mml:mi> </mml:mrow> </mml:math> , $$B_s\rightarrow K \mu \tau $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> </mml:msub> <mml:mo>→</mml:mo> <mml:mi>K</mml:mi> <mml:mi>μ</mml:mi> <mml:mi>τ</mml:mi> </mml:mrow> </mml:math> and $$B_s\rightarrow \phi \mu \tau $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> </mml:msub> <mml:mo>→</mml:mo> <mml:mi>ϕ</mml:mi> <mml:mi>μ</mml:mi> <mml:mi>τ</mml:mi> </mml:mrow> </mml:math> . Lastly, we discuss the validity of the EFT description of LHC data and the impact of loop corrections in our analysis.

Topics & Concepts