Long-lived ${{\widetilde{\mathit q}}}$ (Squark) mass limit

INSPIRE   PDGID:
S046SSQ
The following are bounds on long-lived scalar quarks, assumed to hadronise into hadrons with lifetime long enough to escape the detector prior to a possible decay. Limits may depend on the mixing angle of mass eigenstates: ${{\widetilde{\mathit q}}_{{{1}}}}={{\widetilde{\mathit q}}_{{{L}}}}$cos $\theta _{{{\mathit q}}}+{{\widetilde{\mathit q}}_{{{R}}}}$sin$\theta _{{{\mathit q}}}$. The coupling to the ${{\mathit Z}^{0}}$ boson vanishes for up-type squarks when $\theta _{{{\mathit u}}}=0.98$, and for down type squarks when $\theta _{{{\mathit d}}}=1.17$.
VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$\bf{> 1250}$ 95 1
AABOUD
2019AT
ATLS ${{\widetilde{\mathit b}}}$ ${{\mathit R}}$-hadrons
$\bf{> 1340}$ 95 2
AABOUD
2019AT
ATLS ${{\widetilde{\mathit t}}}$ ${{\mathit R}}$-hadrons
$> 1600$ 95 3
SIRUNYAN
2019BH
CMS long-lived ${{\widetilde{\mathit t}}}$, RPV, ${{\widetilde{\mathit t}}}$ $\rightarrow$ ${{\overline{\mathit d}}}{{\overline{\mathit d}}}$, 10 mm $<$ c${{\mathit \tau}}<$ 110 mm
$\bf{> 1350}$ 95 3
SIRUNYAN
2019BH
CMS long-lived ${{\widetilde{\mathit t}}}$, RPV, ${{\widetilde{\mathit t}}}$ $\rightarrow$ ${{\mathit b}}{{\mathit \ell}}$, 7 mm $<$ c${{\mathit \tau}}<$ 110 mm
$> 805$ 95 4
AABOUD
2016B
ATLS ${{\widetilde{\mathit b}}}$ ${{\mathit R}}$-hadrons
$> 890$ 95 5
AABOUD
2016B
ATLS ${{\widetilde{\mathit t}}}{{\mathit R}}$-hadrons
$> 1040$ 95 6
KHACHATRYAN
2016BW
CMS ${{\widetilde{\mathit t}}}$ R-hadrons, cloud interaction model
$> 1000$ 95 6
KHACHATRYAN
2016BW
CMS ${{\widetilde{\mathit t}}}$ R-hadrons, charge-suppressed interaction model
$> 845$ 95 7
AAD
2015AE
ATLS ${{\widetilde{\mathit b}}}$ R-hadron, stable, Regge model
$> 900$ 95 7
AAD
2015AE
ATLS ${{\widetilde{\mathit t}}}$ R-hadron, stable, Regge model
$>1500$ 95 7
AAD
2015AE
ATLS ${{\widetilde{\mathit g}}}$ decaying to 300 GeV stable sleptons, LeptoSUSY model
$> 751$ 95 8
AAD
2015BM
ATLS ${{\widetilde{\mathit b}}}$ R-hadron, stable, Regge model
$> 766$ 95 8
AAD
2015BM
ATLS ${{\widetilde{\mathit t}}}$ R-hadron, stable, Regge model
$> 525$ 95 9
KHACHATRYAN
2015AK
CMS ${{\widetilde{\mathit t}}}$ R-hadrons, 10 ${{\mathit \mu}}$s$<{{\mathit \tau}}<$1000 s
$> 470$ 95 9
KHACHATRYAN
2015AK
CMS ${{\widetilde{\mathit t}}}$ R-hadrons, 1 ${{\mathit \mu}}$s$<$ ${{\mathit \tau}}<$1000 s
• • We do not use the following data for averages, fits, limits, etc. • •
$> 683$ 95 10
AAD
2013AA
ATLS ${{\widetilde{\mathit t}}}$, ${{\mathit R}}$-hadrons, generic interaction model
$> 612$ 95 11
AAD
2013AA
ATLS ${{\widetilde{\mathit b}}}$, ${{\mathit R}}$-hadrons, generic interaction model
$> 344$ 95 12
AAD
2013BC
ATLS R-hadrons, ${{\widetilde{\mathit t}}}$ $\rightarrow$ ${{\mathit b}}{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}$, Regge model, lifetime between $10^{-5}$ and $10^{3}$ s, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}}$ = 100 GeV
$> 379$ 95 13
AAD
2013BC
ATLS R-hadrons, ${{\widetilde{\mathit t}}}$ $\rightarrow$ ${{\mathit t}}{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}$, Regge model, lifetime between $10^{-5}$ and $10^{3}$ s, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}}$ = 100 GeV
$> 935$ 95 14
CHATRCHYAN
2013AB
CMS long-lived ${{\widetilde{\mathit t}}}$ forming R-hadrons, cloud interaction model
1  AABOUD 2019AT searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for metastable and stable ${{\mathit R}}$-hadrons. Multiple search strategies for a wide range of lifetimes, corresponding to path lengths of a few meters, are defined. No significant deviations from the expected Standard Model background are observed. Sbottom ${{\mathit R}}$-hadrons are excluded at 95$\%$ C.L. for masses below 1250 GeV. Less stringent constraints are achieved with the muon-spectrometer agnostic analysis. See their Figure 9 (bottom-left).
2  AABOUD 2019AT searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for metastable and stable ${{\mathit R}}$-hadrons. Multiple search strategies for a wide range of lifetimes, corresponding to path lengths of a few meters, are defined. No significant deviations from the expected Standard Model background are observed. Stop ${{\mathit R}}$-hadrons are excluded at 95$\%$ C.L. for masses below 1340 GeV. Similar constraints are achieved with the muon-spectrometer agnostic analysis. See their Figure 9 (bottom-right).
3  SIRUNYAN 2019BH searched in 35.9 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for long-lived particles decaying into jets, with each long-lived particle having a decay vertex well displaced from the production vertex. The selected events are found to be consistent with standard model predictions. Limits are set on the gluino mass in a GMSB model where the gluino is decaying via ${{\widetilde{\mathit g}}}$ $\rightarrow$ ${{\mathit g}}{{\widetilde{\mathit G}}}$, see their Figure 4 and in an RPV model of supersymmetry where the gluino is decaying via ${{\widetilde{\mathit g}}}$ $\rightarrow$ ${{\overline{\mathit t}}}{{\overline{\mathit b}}}{{\overline{\mathit s}}}$, see their Figures 5. Limits are also set on the stop mass in two RPV models, see their Figure 6 (for ${{\widetilde{\mathit t}}}$ $\rightarrow$ ${{\mathit b}}{{\mathit \ell}}$ decays) and Figure 7 (for ${{\widetilde{\mathit t}}}$ $\rightarrow$ ${{\overline{\mathit d}}}{{\overline{\mathit d}}}$ decays).
4  AABOUD 2016B searched in 3.2 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for long-lived ${{\mathit R}}$-hadrons using observables related to large ionization losses and slow propagation velocities, which are signatures of heavy charged particles traveling significantly slower than the speed of light. Exclusion limits at 95$\%$ C.L. are set on the long-lived sbottom masses exceeding 805 GeV. See their Fig. 5.
5  AABOUD 2016B searched in 3.2 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for long-lived ${{\mathit R}}$-hadrons using observables related to large ionization losses and slow propagation velocities, which are signatures of heavy charged particles traveling significantly slower than the speed of light. Exclusion limits at 95$\%$ C.L. are set on the long-lived stop masses exceeding 890 GeV. See their Fig. 5.
6  KHACHATRYAN 2016BW searched in 2.5 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for events with heavy stable charged particles, identified by their anomalously high energy deposits in the silicon tracker and/or long time-of-flight measurements by the muon system. No evidence for an excess over the expected background is observed. Limits are derived for pair production of top squarks as a function of mass, depending on the interaction model, see Fig. 4 and Table 7.
7  AAD 2015AE searched in 19.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for heavy long-lived charged particles, measured through their specific ionization energy loss in the ATLAS pixel detector or their time-of-flight in the ALTAS muon system. In the absence of an excess of events above the expected backgrounds, limits are set R-hadrons in various scenarios, see Fig. 11. Limits are also set in LeptoSUSY models where the gluino decays to stable 300 GeV leptons, see Fig. 9.
8  AAD 2015BM searched in 18.4 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for stable and metastable non-relativistic charged particles through their anomalous specific ionization energy loss in the ATLAS pixel detector. In absence of an excess of events above the expected backgrounds, limits are set on stable bottom and top squark R-hadrons, see Table 5.
9  KHACHATRYAN 2015AK looked in a data set corresponding to fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV, and a search interval corresponding to 281 h of trigger lifetime, for long-lived particles that have stopped in the CMS detector. No evidence for an excess over the expected background in a cloud interaction model is observed. Assuming the decay ${{\widetilde{\mathit t}}}$ $\rightarrow$ ${{\mathit t}}{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}$ and lifetimes between 1 ${{\mathit \mu}}$s and 1000 s, limits are derived on ${{\widetilde{\mathit t}}}$ production as a function of ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}}$, see Figs. 4 and 7. The exclusions require that ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}}$ is kinematically consistent with the minimum values of the jet energy thresholds used.
10  AAD 2013AA searched in 4.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for events containing colored long-lived particles that hadronize forming ${{\mathit R}}$-hadrons. No significant excess above the expected background was found. Long-lived ${{\mathit R}}$-hadrons containing a ${{\widetilde{\mathit t}}}$ are excluded for masses up to 683 GeV at 95$\%$ C.L in a general interaction model. Also, limits independent of the fraction of ${{\mathit R}}$-hadrons that arrive charged in the muon system were derived, see Fig. 6.
11  AAD 2013AA searched in 4.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for events containing colored long-lived particles that hadronize forming ${{\mathit R}}$-hadrons. No significant excess above the expected background was found. Long-lived ${{\mathit R}}$-hadrons containing a ${{\widetilde{\mathit b}}}$ are excluded for masses up to 612 GeV at 95$\%$ C.L in a general interaction model. Also, limits independent of the fraction of ${{\mathit R}}$-hadrons that arrive charged in the muon system were derived, see Fig. 6.
12  AAD 2013BC searched in 5.0 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV and in 22.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for bottom squark R-hadrons that have come to rest within the ATLAS calorimeter and decay at some later time to hadronic jets and a neutralino. In absence of an excess of events above the expected backgrounds, limits are set on sbottom masses for the decay ${{\widetilde{\mathit b}}}$ $\rightarrow$ ${{\mathit b}}{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}$, for different lifetimes, and for a neutralino mass of 100 GeV, see their Table 6 and Fig 10.
13  AAD 2013BC searched in 5.0 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV and in 22.9 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for bottom squark R-hadrons that have come to rest within the ATLAS calorimeter and decay at some later time to hadronic jets and a neutralino. In absence of an excess of events above the expected backgrounds, limits are set on stop masses for the decay ${{\widetilde{\mathit t}}}$ $\rightarrow$ ${{\mathit t}}{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}$, for different lifetimes, and for a neutralino mass of 100 GeV, see their Table 6 and Fig 10.
14  CHATRCHYAN 2013AB looked in 5.0 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV and in 18.8 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for events with heavy stable particles, identified by their anomalous dE/dx in the tracker or additionally requiring that it be identified as muon in the muon chambers, from pair production of ${{\widetilde{\mathit t}}_{{{1}}}}$'s. No evidence for an excess over the expected background is observed. Limits are derived for pair production of stops as a function of mass in the cloud interaction model (see Fig. 8 and Table 6). In the charge-suppressed model, the limit decreases to 818 GeV.
References