Tracking down quirks at the Large Hadron Collider

Abstract

Non-helical tracks are the smoking gun signature of charged and/or colored quirks, which are pairs of particles bound by a new, long-range confining force. We propose a method to efficiently search for these non-helical tracks at the LHC, without the need to fit their trajectories. We show that the hits corresponding to quirky trajectories can be selected efficiently by searching for co-planar hits in the inner layers of the ATLAS and CMS trackers, even in the presence of on average 50 pile-up vertices. We further argue that backgrounds from photon conversions and unassociated pile-up hits can be removed almost entirely, while maintaining a signal reconstruction efficiency as high as ∼70%.With the 300 fb −1 dataset, this implies a discovery potential for string tension between 100 eV and 30 keV, and colored (electroweak charged) quirks as heavy as 1600 (650) GeV may be discovered.

Searching for metastable particles with sub-millimeter displaced vertices at hadron colliders

“…Such a long-lived particle is also found in the gauge-mediation models [5][6][7][8], in R-parity violating models [9][10][11], in SUSY axion models [12][13][14][15][16][17][18], in the stealth SUSY scenario [19][20][21], in the SUSY relaxion models [22,23], and in a degenerate SUSY spectrum [24][25][26][27][28][29][30][31][32][33][34]. Other well-motivated scenarios such as Neutral Naturalness [35][36][37][38][39], hidden-valley models [40][41][42][43][44], composite Higgs models [45], dark matter models [46][47][48][49], and neutrino models [50][51][52]…”

Collider searches for long-lived particles beyond the Standard Model

“…As a result, the dark gluon flux tube does not break easily and instead causes the quirks to have macroscopic oscillations before they eventually annihilate. This leads to exotic signatures [80], particularly when the quirk is electrically charged. Figure 6: Production of the long-lived glueballs G 0 ++ (left) and G 2 ++ (right) at a hadron collider through Higgs decay, and their subsequent decay into SM particles X or G ++ 0 and SM particles via Higgs decay.…”

Stopping quirks at the LHC

“…Limits from HSCP and monojet searches [29] are shown in green and blue, respectively. The proposed planar hit search [31] is shown in purple for 300 fb −1 . The limit on E -like quirks from D0 [26] is shown in gray.…”

“…7 For E -like quirks, we include the limit from the D0 (in gray) [26]. Via dashed lines of the same colors we show projections to 300 fb −1 , adding (in purple) the projections for the planar hit reconstruction proposal [31]. We note that the dashed red lines illustrating the out-of-time decay search assume both the search and bunch train patterns remain identical in the larger dataset.…”

“…For length scales larger than the detector size ( 10 m), where the effect of the string force is minimal, heavy stable charged particle (HSCP) searches [30] are able to place stringent limits on quirks [29]. A proposal to look in the monojet sample for coplanar hits that are unmatched to tracks may cover intermediate length scales (1 mm 1 m) [31]. These efforts are only the first steps made in accessing the variety of novel quirky signatures that could potentially be discovered at colliders.…”