Search for long-lived particles using out-of-time trackless jets in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration
JHEP 07 (2023) 210, 2023.

Abstract (data abstract)
A search for long-lived particles decaying in the outer regions of the CMS silicon tracker or in the calorimeters is presented. The search is based on a data sample of proton-proton collisions at $\sqrt{s} = 13$ TeV recorded with the CMS detector at the LHC in 2016-2018, corresponding to an integrated luminosity of 138 $\text{fb}^{-1}$. A novel technique, using trackless and out-of-time jet information combined in a deep neural network discriminator, is employed to identify decays of long-lived particles. The results are interpreted in a simplified model of chargino-neutralino production, where the neutralino is the next-to-lightest supersymmetric particle, is long-lived, and decays to a gravitino and either a Higgs or $Z$ boson.This search is most sensitive to neutralino proper decay lengths of approximately 0.5 m, for which masses up to 1.18 TeV are excluded at 95% confidence level. The current search is the best result to date in the mass range from the kinematic limit imposed by the Higgs mass up to 1.8 TeV.

  • Table 1

    Data from Table 1

    10.17182/hepdata.135827.v2/t1

    Summary of combined statistical and systematic uncertainties, the size of their effect, and whether it applies to the signal or...

  • Figure 1a

    Figure 1 (left), located on page 2.

    10.17182/hepdata.135827.v2/t2

    Feynman diagrams of the effective neutralino pair production in the GMSB simplified model in which the two neutralinos decay into...

  • Figure 1b

    Figure 1 (center), located on page 2.

    10.17182/hepdata.135827.v2/t3

    Feynman diagrams of the effective neutralino pair production in the GMSB simplified model in which the two neutralinos decay into...

  • Figure 1c

    Figure 1 (right), located on page 2.

    10.17182/hepdata.135827.v2/t4

    Feynman diagrams of the effective neutralino pair production in the GMSB simplified model in which the two neutralinos decay into...

  • Figure 2a

    Figure 2 (upper left), located on page 9.

    10.17182/hepdata.135827.v2/t5

    The distributions of the most impactful input variables to the TD jet tagger for signal (red, lighter) and collision background...

  • Figure 2b

    Figure 2 (upper right), located on page 9.

    10.17182/hepdata.135827.v2/t6

    The distributions of the most impactful input variables to the TD jet tagger for signal (red, lighter) and collision background...

  • Figure 2c

    Figure 2 (middle left), located on page 9.

    10.17182/hepdata.135827.v2/t7

    The distributions of the most impactful input variables to the TD jet tagger for signal (red, lighter) and collision background...

  • Figure 2d

    Figure 2 (middle right), located on page 9.

    10.17182/hepdata.135827.v2/t8

    The distributions of the most impactful input variables to the TD jet tagger for signal (red, lighter) and collision background...

  • Figure 2e

    Figure 2 (lower), located on page 9.

    10.17182/hepdata.135827.v2/t9

    The distributions of the most impactful input variables to the TD jet tagger for signal (red, lighter) and collision background...

  • Figure 3a

    Figure 3 (left), located on page 10.

    10.17182/hepdata.135827.v2/t10

    TD jet tagger score distributions (left) for signal (red, lighter) and collision background (blue, darker). Identification probability for the signal...

  • Figure 3b

    Figure 3 (right), located on page 10.

    10.17182/hepdata.135827.v2/t11

    TD jet tagger score distributions (left) for signal (red, lighter) and collision background (blue, darker). Identification probability for the signal...

  • Figure 4

    Figure 4, located on page 10.

    10.17182/hepdata.135827.v2/t12

    The efficiency of the TD jet tagger working point used in the analysis is shown as a function of the...

  • Figure 5

    Figure 5, located on page 11.

    10.17182/hepdata.135827.v2/t13

    The TD jet tagger score distributions for simulation (shaded histogram) and data (black markers) when using electrons from $W\to e\nu_e$...

  • Figure 6a

    Figure 6 (left), located on page 13.

    10.17182/hepdata.135827.v2/t14

    The TD jet tagger misidentification probability measured using the nominal $W$+jets MR (black round markers) is shown along with the...

  • Figure 6b

    Figure 6 (right), located on page 13.

    10.17182/hepdata.135827.v2/t15

    The TD jet tagger misidentification probability measured using the nominal $W$+jets MR (black round markers) is shown along with the...

  • Figure 7

    Figure 7, located on page 15.

    10.17182/hepdata.135827.v2/t16

    Distribution of the number of TD tagged jets for the $m_{\chi} = 400$ GeVsimulated signal samples with $c\tau_{\chi} = 0.5$...

  • Figure 8a

    Figure 8 (left), located on page 16.

    10.17182/hepdata.135827.v2/t17

    Expected and observed 95% CL upper limits on $\sigma_{\chi\chi}$ as functions of $m_\chi$ in a scenario with $\mathcal{B}(\chi\to HG) =...

  • Figure 8b

    Figure 8 (right), located on page 16.

    10.17182/hepdata.135827.v2/t18

    Expected and observed 95% CL upper limits on $\sigma_{\chi\chi}$ as functions of $m_\chi$ in a scenario with $\mathcal{B}(\chi\to HG) =...

  • Figure 9a

    Figure 9 (left), located on page 16.

    10.17182/hepdata.135827.v2/t19

    Expected and observed 95% CL upper limits on $\sigma_{\chi\chi}$ as functions of $c\tau_{\chi}$ in a scenario with $\mathcal{B}(\chi\to H\tilde{G}) =...

  • Figure 9b

    Figure 9 (right), located on page 16.

    10.17182/hepdata.135827.v2/t20

    Expected and observed 95% CL upper limits on $\sigma_{\chi\chi}$ as functions of $c\tau_{\chi}$ in a scenario with $\mathcal{B}(\chi\to H\tilde{G}) =...

  • Figure 10

    Figure 10, located on page 17.

    10.17182/hepdata.135827.v2/t21

    The observed 95% CL upper limit on $\sigma_{\chi\chi}$ as a function of $m_{\chi}$ and $c\tau_{\chi}$ in a scenario with $\mathcal{B}(\chi\to...

  • Figure 11

    Figure 11, located on page 26.

    10.17182/hepdata.135827.v2/t22

    The distribution of the jet charged hadron energy fraction, a variable used as input to the TD jet tagger score,...

  • Figure 12

    Figure 12, located on page 27.

    10.17182/hepdata.135827.v2/t23

    The distribution of the jet neutral hadron energy fraction, a variable used as input to the TD jet tagger score,...

  • Figure 13

    Figure 13, located on page 27.

    10.17182/hepdata.135827.v2/t24

    The distribution of the number of track constituents in the jet, a variable used as input to the TD jet...

  • Figure 14

    Figure 14, located on page 28.

    10.17182/hepdata.135827.v2/t25

    The $\eta$ distribution of TD-tagged jets in a background-enriched control region that comprises events with exactly one TD-tagged jet. Observed...

  • Figure 1 aux

    Figure 1 aux.

    10.17182/hepdata.135827.v2/t26

    Jet time distribution in a sample of b-tagged jets from dilepton $t \bar{t}$ events in 2017 data-taking period (black round...

  • Figure 2 aux

    Figure 2 auxiliary.

    10.17182/hepdata.135827.v2/t27

    The observed 95% CL upper limit on $\sigma_{\chi\chi}$ as a function of $m_{\chi}$ and $c\tau_{\chi}$ in a scenario with $\mathcal{B}(\chi\to...

  • Figure 3 aux

    Figure 3 auxiliary.

    10.17182/hepdata.135827.v2/t28

    The observed 95% CL upper limit on $\sigma_{\chi\chi}$ as a function of $m_{\chi}$ and $c\tau_{\chi}$ in a scenario with $\mathcal{B}(\chi\to...

  • Figure 4 aux

    Figure 4 auxiliary.

    10.17182/hepdata.135827.v2/t29

    The observed 95% CL upper limit on $\sigma_{\chi\chi}$ as a function of $m_{\chi}$ and $c\tau_{\chi}$ in a scenario with $\mathcal{B}(\chi\to...

  • Figure 5 aux

    Figure 5 auxiliary.

    10.17182/hepdata.135827.v2/t30

    The observed 95% CL upper limit on $\sigma_{\chi\chi}$ as a function of $m_{\chi}$ and $c\tau_{\chi}$ in a scenario with $\mathcal{B}(\chi\to...

  • Figure 6 aux

    Figure 6 auxiliary.

    10.17182/hepdata.135827.v2/t31

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 7 aux

    Figure 7 auxiliary.

    10.17182/hepdata.135827.v2/t32

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 8 aux

    Figure 8 auxiliary.

    10.17182/hepdata.135827.v2/t33

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 9 aux

    Figure 9 auxiliary.

    10.17182/hepdata.135827.v2/t34

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 10 aux

    Figure 10 auxiliary.

    10.17182/hepdata.135827.v2/t35

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 11 aux

    Figure 11 auxiliary.

    10.17182/hepdata.135827.v2/t36

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 12 aux

    Figure 12 auxiliary.

    10.17182/hepdata.135827.v2/t37

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 13 aux

    Figure 13 auxiliary.

    10.17182/hepdata.135827.v2/t38

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 14 aux

    Figure 14 auxiliary.

    10.17182/hepdata.135827.v2/t39

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 15 aux

    Figure 15 auxiliary.

    10.17182/hepdata.135827.v2/t40

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 16 aux

    Figure 16 auxiliary.

    10.17182/hepdata.135827.v2/t41

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 17 aux

    Figure 17 auxiliary.

    10.17182/hepdata.135827.v2/t42

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 18 aux

    Figure 18 auxiliary.

    10.17182/hepdata.135827.v2/t43

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 19 aux

    Figure 19 auxiliary.

    10.17182/hepdata.135827.v2/t44

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 20 aux

    Figure 20 auxiliary.

    10.17182/hepdata.135827.v2/t45

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 21 aux

    Figure 21 auxiliary.

    10.17182/hepdata.135827.v2/t46

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 22 aux

    Figure 22 auxiliary.

    10.17182/hepdata.135827.v2/t47

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 23 aux

    Figure 23 auxiliary.

    10.17182/hepdata.135827.v2/t48

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 24 aux

    Figure 24 auxiliary.

    10.17182/hepdata.135827.v2/t49

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 25 aux

    Figure 25 auxiliary.

    10.17182/hepdata.135827.v2/t50

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 26 aux

    Figure 26 auxiliary.

    10.17182/hepdata.135827.v2/t51

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 27 aux

    Figure 27 auxiliary.

    10.17182/hepdata.135827.v2/t52

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 28 aux

    Figure 28 auxiliary.

    10.17182/hepdata.135827.v2/t53

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 29 aux

    Figure 29 auxiliary.

    10.17182/hepdata.135827.v2/t54

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 30 aux

    Figure 30 auxiliary.

    10.17182/hepdata.135827.v2/t55

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 31 aux

    Figure 31 auxiliary.

    10.17182/hepdata.135827.v2/t56

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 32 aux

    Figure 32 auxiliary.

    10.17182/hepdata.135827.v2/t57

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 33 aux

    Figure 33 auxiliary.

    10.17182/hepdata.135827.v2/t58

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 34 aux

    Figure 34 auxiliary.

    10.17182/hepdata.135827.v2/t59

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 35 aux

    Figure 35 auxiliary.

    10.17182/hepdata.135827.v2/t60

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 36 aux

    Figure 36 auxiliary.

    10.17182/hepdata.135827.v2/t61

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 37 aux

    Figure 37 auxiliary.

    10.17182/hepdata.135827.v2/t62

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 38 aux

    Figure 38 auxiliary.

    10.17182/hepdata.135827.v2/t63

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 39 aux

    Figure 39 auxiliary.

    10.17182/hepdata.135827.v2/t64

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 40 aux

    Figure 40 auxiliary.

    10.17182/hepdata.135827.v2/t65

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 41 aux

    Figure 41 auxiliary.

    10.17182/hepdata.135827.v2/t66

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 42 aux

    Figure 42 auxiliary.

    10.17182/hepdata.135827.v2/t67

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 43 aux

    Figure 43 auxiliary.

    10.17182/hepdata.135827.v2/t68

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Figure 44 aux

    Figure 44 auxiliary.

    10.17182/hepdata.135827.v2/t69

    The efficiency of identifying a LLP decay as a TD-tagged jet in bins of the LLP transverse and longitudinal decay...

  • Table 1 aux

    Data from Table 1 aux

    10.17182/hepdata.135827.v2/t70

    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 127 GeV.

  • Table 2 aux

    Data from Table 2 aux

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    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 127 GeV.

  • Table 3 aux

    Data from Table 3 aux

    10.17182/hepdata.135827.v2/t72

    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 150 GeV.

  • Table 4 aux

    Data from Table 4 aux

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    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 150 GeV.

  • Table 5 aux

    Data from Table 5 aux

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    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 175 GeV.

  • Table 6 aux

    Data from Table 6 aux

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    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 175 GeV.

  • Table 7 aux

    Data from Table 7 aux

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    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 200 GeV.

  • Table 8 aux

    Data from Table 8 aux

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    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 200 GeV.

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    Data from Table 9 aux

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    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 250 GeV.

  • Table 10 aux

    Data from Table 10 aux

    10.17182/hepdata.135827.v2/t79

    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 250 GeV.

  • Table 11 aux

    Data from Table 11 aux

    10.17182/hepdata.135827.v2/t80

    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 300 GeV.

  • Table 12 aux

    Data from Table 12 aux

    10.17182/hepdata.135827.v2/t81

    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 300 GeV.

  • Table 13 aux

    Data from Table 13 aux

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    Cutflow table for a $\tilde{\chi}_{1}^{0}$ signal sample with a mass of 400 GeV.

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