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# 2019 Meeting of the Division of Particles & Fields of the American Physical Society

July 29, 2019 to August 2, 2019
Northeastern University
US/Eastern timezone

## Search for displaced vertices of oppositely-charged leptons from decays of long-lived particles in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

Jul 31, 2019, 5:08 PM
17m
Shillman 335 (Northeastern University)

### Shillman 335

#### Northeastern University

Oral Presentation Beyond Standard Model Physics

### Speaker

Prof. K.K. Gan (The Ohio State University (US))

### Description

A search for long-lived particles decaying to an oppositely-charged lepton pair, $\mu\mu$, $ee$, or $e\mu$?, is presented
using 32.8 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s}$ = 13 TeV by the ATLAS detector at the LHC.
Candidate leptons are required to form a vertex, within the inner tracking volume of ATLAS, displaced
from the primary pp interaction region. No lepton pairs with an invariant mass greater than 12 GeV are
observed, consistent with the background expectations derived from data. The result is interpreted in
a supersymmetric model in which the lightest neutralino, produced via squark-antisquark production,
decays to $\ell^+\ell'^-\nu (\ell = e, \mu)$ with a finite lifetime due to the presence of R-parity violating couplings.
Cross section limits are presented for specific squark and neutralino masses. For a 700 GeV squark,
neutralinos with mass of 50–500 GeV and proper mean lifetimes corresponding to $c\tau$? of 1 mm to 6 m
are excluded. For a 1.6 TeV squark, 3 mm to 1 m are excluded for 1.3 TeV neutralinos.

### Primary author

Prof. K.K. Gan (The Ohio State University (US))