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CMS-EXO-24-028 ; CERN-EP-2026-048
A search for microscopic black holes, string balls, and sphalerons in proton-proton collisions at $ \sqrt{s} = $ 13 TeV
Submitted to the Journal of High Energy Physics
Abstract: A search for microscopic black holes, string balls, and electroweak sphalerons using proton-proton collisions at $ \sqrt{s} = $ 13 TeV recorded with the CMS detector at the CERN LHC during the 2016--2018 data taking, and corresponding to an integrated luminosity of 138 fb$ ^{-1} $, is presented. Two search strategies based on control samples in data are used. Model-independent limits on the cross section of physics phenomena with multiple energetic jets, leptons, and photons are set using a method that relies on the shape invariance of the scalar sum of the transverse momenta of all objects in the event. Model-dependent limits on black hole and sphaleron production are set using a newly introduced method that has been developed for the identification of collider events with distinct kinematic features by separating them into classes based on phase space proximity. In the context of models with large extra dimensions, semiclassical black holes and string balls with masses below 8.4--11.4 TeV and 9.0--10.7 TeV, respectively, are excluded at 95% confidence level, significantly extending the reach beyond previous searches. Results of a dedicated search for electroweak sphalerons are used to derive an upper limit of 0.0034 at 95% confidence level on the fraction of quark-quark interactions above the nominal sphaleron transition energy threshold of 9 TeV.
Figures & Tables Summary References CMS Publications
Figures

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Figure 1:
The $ S_\text{T} $ (left) and sphericity (right) distributions for various BH (with $ n = $ 2) and sphaleron signal models are plotted along with the corresponding distributions for simulated QCD multijet background events. The distributions are normalized to unit area.

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Figure 1-a:
The $ S_\text{T} $ (left) and sphericity (right) distributions for various BH (with $ n = $ 2) and sphaleron signal models are plotted along with the corresponding distributions for simulated QCD multijet background events. The distributions are normalized to unit area.

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Figure 1-b:
The $ S_\text{T} $ (left) and sphericity (right) distributions for various BH (with $ n = $ 2) and sphaleron signal models are plotted along with the corresponding distributions for simulated QCD multijet background events. The distributions are normalized to unit area.

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Figure 2:
The SVM score distributions for simulated QCD multijets, and selected BH (with $ n = $ 2) and sphaleron models, before (left) and after (right) the sphericity requirement. The distributions are normalized to unit area.

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Figure 2-a:
The SVM score distributions for simulated QCD multijets, and selected BH (with $ n = $ 2) and sphaleron models, before (left) and after (right) the sphericity requirement. The distributions are normalized to unit area.

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Figure 2-b:
The SVM score distributions for simulated QCD multijets, and selected BH (with $ n = $ 2) and sphaleron models, before (left) and after (right) the sphericity requirement. The distributions are normalized to unit area.

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Figure 3:
The SVM score vs. the $ S_\text{T} $ distributions for simulated QCD multijet background (left) and the BH signal model B1 with $ M_\text{D} = $ 2 TeV, $ M_\text{BH} = $ 10 TeV, and $ n = $ 2 (right), after the $ S > $ 0.1 selection.

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Figure 3-a:
The SVM score vs. the $ S_\text{T} $ distributions for simulated QCD multijet background (left) and the BH signal model B1 with $ M_\text{D} = $ 2 TeV, $ M_\text{BH} = $ 10 TeV, and $ n = $ 2 (right), after the $ S > $ 0.1 selection.

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Figure 3-b:
The SVM score vs. the $ S_\text{T} $ distributions for simulated QCD multijet background (left) and the BH signal model B1 with $ M_\text{D} = $ 2 TeV, $ M_\text{BH} = $ 10 TeV, and $ n = $ 2 (right), after the $ S > $ 0.1 selection.

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Figure 4:
The $ S_\text{T} $ distribution in the $ N \geq $ 4 (left) and $ N \geq $ 7 (right) in the SI-VR in data is indicated by the black dots. The background prediction is represented by the red line, and the gray band corresponds to the background modeling uncertainty. The lower panels show the difference between observed data and the background prediction, normalized by the total uncertainty.

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Figure 4-a:
The $ S_\text{T} $ distribution in the $ N \geq $ 4 (left) and $ N \geq $ 7 (right) in the SI-VR in data is indicated by the black dots. The background prediction is represented by the red line, and the gray band corresponds to the background modeling uncertainty. The lower panels show the difference between observed data and the background prediction, normalized by the total uncertainty.

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Figure 4-b:
The $ S_\text{T} $ distribution in the $ N \geq $ 4 (left) and $ N \geq $ 7 (right) in the SI-VR in data is indicated by the black dots. The background prediction is represented by the red line, and the gray band corresponds to the background modeling uncertainty. The lower panels show the difference between observed data and the background prediction, normalized by the total uncertainty.

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Figure 5:
Post-fit $ S_\text{T} $ distributions in VR-FAIL (left) and VR-PASS (right) regions in data. The gray hatched areas include both statistical and systematic uncertainties in the background prediction (yellow histogram). The red line corresponds to the signal model B1, with $ M_\text{D} = $ 2 TeV, $ M_\text{BH} = $ 10 TeV, and $ n = $ 2. The lower panels show the difference between observed data and the background prediction, normalized by the total uncertainty.

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Figure 6:
The $ S_\text{T} $ distribution in the $ N \geq $ 4 (left) and $ N \geq $ 7 (right) SI-SR in data, indicated by the black dots, along with the background prediction and its uncertainty represented by the red line and gray band, respectively. Lower panel as in Fig. 4.

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Figure 6-a:
The $ S_\text{T} $ distribution in the $ N \geq $ 4 (left) and $ N \geq $ 7 (right) SI-SR in data, indicated by the black dots, along with the background prediction and its uncertainty represented by the red line and gray band, respectively. Lower panel as in Fig. 4.

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Figure 6-b:
The $ S_\text{T} $ distribution in the $ N \geq $ 4 (left) and $ N \geq $ 7 (right) SI-SR in data, indicated by the black dots, along with the background prediction and its uncertainty represented by the red line and gray band, respectively. Lower panel as in Fig. 4.

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Figure 7:
Expected and observed model-independent 95% CL upper limits on the cross section times acceptance for multiplicity $ N \geq $ 4, where the inner (outer) band represents the 68% (95%) quantile of the expected limit (left), and the observed limits with different minimum object multiplicity requirements (right).

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Figure 7-a:
Expected and observed model-independent 95% CL upper limits on the cross section times acceptance for multiplicity $ N \geq $ 4, where the inner (outer) band represents the 68% (95%) quantile of the expected limit (left), and the observed limits with different minimum object multiplicity requirements (right).

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Figure 7-b:
Expected and observed model-independent 95% CL upper limits on the cross section times acceptance for multiplicity $ N \geq $ 4, where the inner (outer) band represents the 68% (95%) quantile of the expected limit (left), and the observed limits with different minimum object multiplicity requirements (right).

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Figure 8:
Post-fit $ S_\text{T} $ distributions in the FAIL (left) and PASS (right) regions in data. The gray shaded area includes both statistical and systematic uncertainties in the background prediction (yellow histogram) while the red and blue lines are B1 signal examples, as noted in the legends. Lower panel as in Fig. 5.

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Figure 9:
Expected and observed 95% CL upper limits on the cross section for a semiclassical nonrotating BH model (B1) with $ n = $ 2 and $ M_\text{D} = $ 2 TeV (left) or $ M_\text{D} = $ 4 TeV (right), as a function of $ M_\text{BH} $. The blue curves represent the theoretical cross section values. The inner (outer) band represents the 68% (95%) quantile of the expected limit.

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Figure 9-a:
Expected and observed 95% CL upper limits on the cross section for a semiclassical nonrotating BH model (B1) with $ n = $ 2 and $ M_\text{D} = $ 2 TeV (left) or $ M_\text{D} = $ 4 TeV (right), as a function of $ M_\text{BH} $. The blue curves represent the theoretical cross section values. The inner (outer) band represents the 68% (95%) quantile of the expected limit.

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Figure 9-b:
Expected and observed 95% CL upper limits on the cross section for a semiclassical nonrotating BH model (B1) with $ n = $ 2 and $ M_\text{D} = $ 2 TeV (left) or $ M_\text{D} = $ 4 TeV (right), as a function of $ M_\text{BH} $. The blue curves represent the theoretical cross section values. The inner (outer) band represents the 68% (95%) quantile of the expected limit.

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Figure 10:
Excluded $ M_{\text{BH}}^{\text{min}} $ values as functions of $ M_\text{D} $ and $ n $ for a variety of BLACKMAX (left) and CHARYBDIS2 (right) BH models.

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Figure 10-a:
Excluded $ M_{\text{BH}}^{\text{min}} $ values as functions of $ M_\text{D} $ and $ n $ for a variety of BLACKMAX (left) and CHARYBDIS2 (right) BH models.

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Figure 10-b:
Excluded $ M_{\text{BH}}^{\text{min}} $ values as functions of $ M_\text{D} $ and $ n $ for a variety of BLACKMAX (left) and CHARYBDIS2 (right) BH models.

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Figure 11:
Expected and observed 95% CL upper limits for SB models with $ M_{\text{S}} = $ 3.5 TeV and $ g_{\text{S}} = $ 0.2 (left) and excluded SB mass values as functions of $ M_{\text{S}} $ at $ g_{\text{S}}=0.2, $ 0.3, and 0.4 (right). The inner (outer) band represents the 68% (95%) quantile of the expected limit.

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Figure 11-a:
Expected and observed 95% CL upper limits for SB models with $ M_{\text{S}} = $ 3.5 TeV and $ g_{\text{S}} = $ 0.2 (left) and excluded SB mass values as functions of $ M_{\text{S}} $ at $ g_{\text{S}}=0.2, $ 0.3, and 0.4 (right). The inner (outer) band represents the 68% (95%) quantile of the expected limit.

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Figure 11-b:
Expected and observed 95% CL upper limits for SB models with $ M_{\text{S}} = $ 3.5 TeV and $ g_{\text{S}} = $ 0.2 (left) and excluded SB mass values as functions of $ M_{\text{S}} $ at $ g_{\text{S}}=0.2, $ 0.3, and 0.4 (right). The inner (outer) band represents the 68% (95%) quantile of the expected limit.

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Figure 12:
Expected and observed 95% CL upper limits on the pre-exponential factor for the sphaleron model with $ p({N_\text{CS}})= $ 0.5 (left), and observed limits with $ p({N_\text{CS}})= $ 0, 0.5, and 1 (right). The inner (outer) band (left) represents the 68% (95%) quantiles of the expected limit.

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Figure 12-a:
Expected and observed 95% CL upper limits on the pre-exponential factor for the sphaleron model with $ p({N_\text{CS}})= $ 0.5 (left), and observed limits with $ p({N_\text{CS}})= $ 0, 0.5, and 1 (right). The inner (outer) band (left) represents the 68% (95%) quantiles of the expected limit.

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Figure 12-b:
Expected and observed 95% CL upper limits on the pre-exponential factor for the sphaleron model with $ p({N_\text{CS}})= $ 0.5 (left), and observed limits with $ p({N_\text{CS}})= $ 0, 0.5, and 1 (right). The inner (outer) band (left) represents the 68% (95%) quantiles of the expected limit.
Tables

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Table 1:
Parameter combinations of the fundamental Planck scale $ M_\text{D} $ and minimum black hole mass $ M_{\text{BH}}^{\text{min}} $ (both in TeV) that exclude a given number of extra dimensions $ n^{\text{max}} $, for BH models generated with BLACKMAX and CHARYBDIS2. Each row collects all ($ M_\text{D} $, $ M_{\text{BH}}^{\text{min}} $) pairs yielding the same exclusion level. Combinations with $ M_{\text{BH}}^{\text{min}} < M_\text{D} $ are unphysical and not considered. The first row indicates the pairs that are excluded for any number of extra dimensions in the ADD model, while the last row shows the parameters where no exclusion could be made in this analysis.
Summary
A dedicated search for black holes, string balls, and sphalerons produced in proton-proton collisions at $ \sqrt{s} = $ 13 TeV using data collected with the CMS detector has been presented. No excesses above the standard model background predictions are observed. We set 95% confidence level (CL) model-independent limits on cross section of hypothetical signals characterized by a large multiplicity of energetic jets, leptons, and photons. The model-independent results demonstrate approximately a factor of four improvement in the cross section limit compared to the previous CMS analysis. The model-dependent results exclude at 95% CL semiclassical black holes and string balls with masses below 8.4--11.4 TeV and 9.0--10.7 TeV, respectively, depending on the model and the number of extra dimensions. This extends the exclusion reach by 1--1.6 TeV and 1.3--1.9 TeV, respectively. The observed (expected) upper limit on the sphaleron pre-exponential factor for the nominal electroweak sphaleron transition energy of 9 TeV is 0.0034 (0.0035) at 95% CL, which is strengthened by a factor of 6.2 (3.4) compared to the previous best limit of 0.021 (0.012) from CMS [21]. These are the most stringent limits on the sphaleron pre-exponential factor to date. A significant improvement in the model-dependent study over previous results comes from an improved understanding of parton distribution functions. Additional significant gains can be traced to both the increased integrated luminosity, and the enhanced background rejection provided by the sphericity and phase space distance event selection requirements.
References
1 I. Antoniadis, N. Arkani-Hamed, S. Dimopoulos, and G. R. Dvali New dimensions at a millimeter to a fermi and superstrings at a TeV PLB 436 (1998) 257 hep-ph/9804398
2 N. Arkani-Hamed, S. Dimopoulos, and G. R. Dvali The hierarchy problem and new dimensions at a millimeter PLB 429 (1998) 263 hep-ph/9803315
3 N. Arkani-Hamed, S. Dimopoulos, and G. R. Dvali Phenomenology, astrophysics and cosmology of theories with submillimeter dimensions and TeV scale quantum gravity PRD 59 (1999) 086004 hep-ph/9807344
4 L. Randall and R. Sundrum An alternative to compactification PRL 83 (1999) 4690 hep-th/9906064
5 L. Randall and R. Sundrum A large mass hierarchy from a small extra dimension PRL 83 (1999) 3370 hep-ph/9905221
6 S. Dimopoulos and G. L. Landsberg Black holes at the LHC PRL 87 (2001) 161602 hep-ph/0106295
7 P. C. Argyres, S. Dimopoulos, and J. March-Russell Black holes and submillimeter dimensions PLB 441 (1998) 96 hep-th/9808138
8 S. B. Giddings and S. D. Thomas High-energy colliders as black hole factories: The end of short distance physics PRD 65 (2002) 056010 hep-ph/0106219
9 S. W. Hawking Particle creation by black holes [Erratum: doi:10./BF01608497, 1975]
Commun. Math. Phys. 43 (1975) 199
10 P. Meade and L. Randall Black holes and quantum gravity at the LHC JHEP 05 (2008) 003 0708.3017
11 D. M. Gingrich Quantum black holes with charge, colour, and spin at the LHC JPG 37 (2010) 105008 0912.0826
12 X. Calmet, W. Gong, and S. D. H. Hsu Colorful quantum black holes at the LHC PLB 668 (2008) 20 0806.4605
13 S. Dimopoulos and R. Emparan String balls at the LHC and beyond PLB 526 (2002) 393 hep-ph/0108060
14 G. 't Hooft Symmetry breaking through Bell-Jackiw anomalies PRL 37 (1976) 8
15 F. R. Klinkhamer and N. S. Manton A saddle point solution in the Weinberg-Salam theory PRD 30 (1984) 2212
16 S. H. H. Tye and S. S. C. Wong Bloch wave function for the periodic sphaleron potential and unsuppressed baryon and lepton number violating processes PRD 92 (2015) 045005 1505.03690
17 J. Ellis and K. Sakurai Search for sphalerons in proton-proton collisions JHEP 04 (2016) 086 1601.03654
18 A. Papaefstathiou, S. Pl รค tzer, and K. Sakurai On the phenomenology of sphaleron-induced processes at the LHC and beyond JHEP 12 (2019) 017 1910.04761
19 ATLAS Collaboration Search for strong gravity in multijet final states produced in pp collisions at $ \sqrt{s} = $ 13 TeV using the ATLAS detector at the LHC JHEP 03 (2016) 026 1512.02586
20 ATLAS Collaboration Search for quantum black hole production in lepton+jet final states using proton-proton collisions at $ \sqrt{s}= $ 13 TeV with the ATLAS detector PRD 109 (2024) 032010 2307.14967
21 CMS Collaboration Search for black holes and sphalerons in high-multiplicity final states in proton-proton collisions at $ \sqrt{s}= $ 13 TeV JHEP 11 (2018) 042 CMS-EXO-17-023
1805.06013
22 CMS Collaboration Search for microscopic black hole signatures at the Large Hadron Collider PLB 697 (2011) 434 CMS-EXO-10-017
1012.3375
23 CMS Collaboration Search for microscopic black holes in $ pp $ collisions at $ \sqrt{s}= $ 7 TeV JHEP 04 (2012) 061 CMS-EXO-11-071
1202.6396
24 CMS Collaboration Search for microscopic black holes in $ pp $ collisions at $ \sqrt{s} = $ 8 TeV JHEP 07 (2013) 178 CMS-EXO-12-009
1303.5338
25 CMS Collaboration Search for black holes in high-multiplicity final states in proton-proton collisions at $ \sqrt{s}= $13 TeV PLB 774 (2017) 279 CMS-EXO-15-007
1705.01403
26 CMS Collaboration HEPData record for this analysis link
27 CMS Collaboration The CMS experiment at the CERN LHC JINST 3 (2008) S08004 1003.4038
28 CMS Collaboration Development of the CMS detector for the CERN LHC Run 3 JINST 19 (2024) P05064 CMS-PRF-21-001
2309.05466
29 CMS Collaboration Description and performance of track and primary-vertex reconstruction with the CMS tracker JINST 9 (2014) P10009 CMS-TRK-11-001
1405.6569
30 Tracker Group of the CMS Collaboration The CMS phase-1 pixel detector upgrade JINST 16 (2021) P02027 2012.14304
31 CMS Collaboration Track impact parameter resolution for the full pseudo rapidity coverage in the 2017 dataset with the CMS Phase-1 pixel detector CMS Detector Performance Summary CMS-DP-2020-049, 2020
CDS
32 CMS Collaboration 2017 tracking performance plots CMS Detector Performance Summary CMS-DP-2017-015, 2017
CDS
33 CMS Collaboration Performance of the CMS level-1 trigger in proton-proton collisions at $ \sqrt{s} = $ 13 TeV JINST 15 (2020) P10017 CMS-TRG-17-001
2006.10165
34 CMS Collaboration The CMS trigger system JINST 12 (2017) P01020 CMS-TRG-12-001
1609.02366
35 CMS Collaboration Performance of the CMS high-level trigger during LHC Run 2 JINST 19 (2024) P11021 CMS-TRG-19-001
2410.17038
36 D.-C. Dai et al. BlackMax: A black-hole event generator with rotation, recoil, split branes, and brane tension PRD 77 (2008) 076007 0711.3012
37 C. M. Harris, P. Richardson, and B. R. Webber CHARYBDIS: A black hole event generator JHEP 08 (2003) 033 hep-ph/0307305
38 J. A. Frost et al. Phenomenology of production and decay of spinning extra-dimensional black holes at hadron colliders JHEP 10 (2009) 014 0904.0979
39 C. Bravo and J. Hauser BaryoGEN, a Monte Carlo generator for sphaleron-like transitions in proton-proton collisions JHEP 11 (2018) 041 1805.02786
40 R. Frederix et al. The automation of next-to-leading order electroweak calculations [Erratum: doi: 10./JHEP11()085, 2018]
JHEP 07 (2018) 185
1804.10017
41 J. Alwall et al. Comparative study of various algorithms for the merging of parton showers and matrix elements in hadronic collisions EPJC 53 (2008) 473 0706.2569
42 S. Creek, O. Efthimiou, P. Kanti, and K. Tamvakis Greybody factors for brane scalar fields in a rotating black-hole background PRD 75 (2007) 084043 hep-th/0701288
43 S. Creek, O. Efthimiou, P. Kanti, and K. Tamvakis Scalar emission in the bulk in a rotating black hole background PLB 656 (2007) 102 0709.0241
44 H. Yoshino and V. S. Rychkov Improved analysis of black hole formation in high-energy particle collisions [Erratum: doi:10.1103/PhysRevD.77.089905, 2005]
PRD 71 (2005) 104028
hep-th/0503171
45 B. Koch, M. Bleicher, and S. Hossenfelder Black hole remnants at the LHC JHEP 10 (2005) 053 hep-ph/0507138
46 H. Stoecker Stable TeV - black hole remnants at the LHC: Discovery through di-jet suppression, mono-jet emission and a supersonic boom in the quark-gluon plasma Int. J. Mod. Phys. D 16 (2007) 185 hep-ph/0605062
47 F. Scardigli Glimpses on the micro black hole Planck phase Symmetry 12 (2020) 1519 0809.1832
48 D. M. Gingrich and K. Martell Study of highly-excited string states at the Large Hadron Collider PRD 78 (2008) 115009 0808.2512
49 CMS Collaboration Extraction and validation of a new set of CMS PYTHIA8 tunes from underlying-event measurements EPJC 80 (2020) 4 CMS-GEN-17-001
1903.12179
50 NNPDF Collaboration Parton distributions from high-precision collider data EPJC 77 (2017) 663 1706.00428
51 CMS Collaboration Upgrades for the CMS simulation J. Phys. Conf. Ser. 608 (2015) 012056
52 CMS Collaboration Particle-flow reconstruction and global event description with the CMS detector JINST 12 (2017) P10003 CMS-PRF-14-001
1706.04965
53 CMS Collaboration Technical proposal for the Phase-II upgrade of the Compact Muon Solenoid CMS Technical Proposal CERN-LHCC-2015-010, CMS-TDR-15-02, CMS, 2015
CDS
54 CMS Collaboration Jet energy scale and resolution in the CMS experiment in pp collisions at 8 TeV no. 02, P0, 2017
JINST 12 (2017)
CMS-JME-13-004
1607.03663
55 CMS Collaboration Pileup removal algorithms CMS Physics Analysis Summary, CMS, 2014
CMS-PAS-JME-14-001
CMS-PAS-JME-14-001
56 CMS Collaboration Jet algorithms performance in 13 TeV data CMS Physics Analysis Summary, CMS, 2017
link
CMS-PAS-JME-16-003
57 CMS Collaboration Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at $\sqrt{s}$ = 8 TeV JINST 10 (2015) P06005 CMS-EGM-13-001
1502.02701
58 CMS Collaboration Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC JINST 16 (2021) P05014 CMS-EGM-17-001
2012.06888
59 CMS Collaboration Performance of CMS muon reconstruction in pp collision events at $ \sqrt{s}= $ 7 TeV JINST 7 (2012) P10002 CMS-MUO-10-004
1206.4071
60 CMS Collaboration Performance of the CMS muon detector and muon reconstruction with proton-proton collisions at $ \sqrt{s}= $ 13 TeV JINST 13 (2018) P06015 CMS-MUO-16-001
1804.04528
61 CMS Collaboration Performance of missing transverse momentum reconstruction in proton-proton collisions at $ \sqrt{s} = $ 13 TeV using the CMS detector JINST 14 (2019) P07004 CMS-JME-17-001
1903.06078
62 ALEPH Collaboration Studies of quantum chromodynamics with the ALEPH detector Phys. Rept. 294 (1998) 1
63 ATLAS Collaboration Measurement of event shapes at large momentum transfer with the ATLAS detector in pp collisions at $ \sqrt{s}= $ 7 TeV EPJC 72 (2012) 2211 1206.2135
64 ALICE Collaboration Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at $ \sqrt{s}= $ 0.9, 2.76 and 7 TeV EPJC 72 (2012) 2124 1205.3963
65 P. T. Komiske, E. M. Metodiev, and J. Thaler Metric space of collider events PRL 123 (2019) 041801 1902.02346
66 P. T. Komiske, E. M. Metodiev, and J. Thaler The hidden geometry of particle collisions JHEP 07 (2020) 006 2004.04159
67 T. Cai, J. Cheng, K. Craig, and N. Craig Which metric on the space of collider events? PRD 105 (2022) 076003 2111.03670
68 P. T. Komiske et al. Exploring the space of jets with CMS open data PRD 101 (2020) 034009 1908.08542
69 C. Cesarotti and J. Thaler A robust measure of event isotropy at colliders JHEP 08 (2020) 084 2004.06125
70 C. Cesarotti, M. Reece, and M. J. Strassler The efficacy of event isotropy as an event shape observable JHEP 07 (2021) 215 2011.06599
71 L. Gouskos et al. Optimal transport for a novel event description at hadron colliders PRD 108 (2023) 096003 2211.02029
72 ATLAS Collaboration Measurements of multijet event isotropies using optimal transport with the ATLAS detector JHEP 10 (2023) 060 2305.16930
73 A. J. Larkoski and T. Melia Covariantizing phase space PRD 102 (2020) 094014 2008.06508
74 T. Cai et al. The phase space distance between collider events JHEP 09 (2024) 054 2405.16698
75 C. Cortes and V. Vapnik Support-vector networks Mach. Learn. 20 (1995) 273
76 G. Punzi Sensitivity of searches for new signals and its optimization Conf 030908 (2003) MODT002 physics/0308063
77 L. Corcodilos The 2D Alphabet background modeling method and its use in the search for an excited bottom quark PhD thesis, Johns Hopkins University, 2021
link
78 R. A. Fisher On the interpretation of $ \chi^2 $ from contingency tables, and the calculation of p J. Roy. Stat. Soc. 85 (1922) 87
79 S. Baker and R. D. Cousins Clarification of the use of chi-square and likelihood functions in fits to histograms NIM 221 (1984) 437
80 CMS Collaboration Precision luminosity measurement in proton-proton collisions at $ \sqrt{s} = $ 13 TeV with the CMS detector CMS-PAS-LUM-20-001 CMS-PAS-LUM-20-001
81 CMS Collaboration Measurement of the inelastic proton-proton cross section at $ \sqrt{s}= $ 13 TeV JHEP 07 (2018) 161 CMS-FSQ-15-005
1802.02613
82 CMS Collaboration Identification of heavy, energetic, hadronically decaying particles using machine-learning techniques JINST 15 (2020) P06005 CMS-JME-18-002
2004.08262
83 CMS Collaboration Pileup mitigation at CMS in 13 TeV data JINST 15 (2020) P09018 CMS-JME-18-001
2003.00503
84 CMS Collaboration The CMS statistical analysis and combination tool: Combine Comput. Softw. Big Sci. 8 (2024) 19 CMS-CAT-23-001
2404.06614
85 W. Verkerke and D. Kirkby The RooFit toolkit for data modeling in the Int. Conf. on Computing in High Energy and Nuclear Physics (CHEP ): La Jolla CA, United States, March 24--28,, 2003
Proc. 1 (2003) 3
physics/0306116
86 L. Moneta et al. The RooStats project in the Int. Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT ): Jaipur, India, February 22--27,, 2010
Proc. 1 (2010) 3
1009.1003
87 T. Junk Confidence level computation for combining searches with small statistics NIM A 434 (1999) 435 hep-ex/9902006
88 A. L. Read Presentation of search results: The $ CL_s $ technique JPG 28 (2002) 2693
89 ATLAS, CMS, LHC Higgs Combination Group Collaboration Procedure for the LHC Higgs boson search combination in Summer 2011 Technical Report CMS-NOTE-2011-005, ATL-PHYS-PUB-2011-11, CERN, 2011
90 G. Cowan, K. Cranmer, E. Gross, and O. Vitells Asymptotic formulae for likelihood-based tests of new physics [Erratum: doi:10.1140/epjc/s2-013-2501-z, 2011]
EPJC 71 (2011) 1554
1007.1727
Compact Muon Solenoid
LHC, CERN