Physics:List of HEP measurements with largest discrepancies

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Here is a list of experimental measurements in high-energy particle physics (HEP) with largest deviations from either the state-of-the art theory or some data-driven expectation. This list contains only measurements that include "evidence" for some new phenomena, which is defined as measurements with more than 3 "σ" (3 sigma or standard deviations) i.e. 0.3% probability of occurring by chance. The significance is defined as "local", i.e. it does not include look-elsewhere effect.

Intriguing deviations with significance >3 sigma can be signs of new physics. For example, top quarks were first hinted at in the 1994 paper by the CDF collaboration, observing an excess of events amounting to about 3-sigma, but the existence of the top quark was fully established later. However, in most cases, 3 sigma deviations can be due to statistical or some systematic effects that require clarifications by independent measurements.


Description Year Experiment Excess level Comment
Enhancement around 4.5 GeV [1] 2022 BESIII 3.3 σ Not confirmed by others
Higgs search in bbmumu channel at 52 GeV [2] 2022 ATLAS 3.3 σ Not confirmed by CMS
g-2 (muon anomalous magnetic moment)[3] 2021 Muon g−2 3.3 σ No other experiments
Excess of electronic recoil at 1-7 keV [4] 2021 XENON1T 4.0 σ No other experiments
Excess of electron like events[5] 2018 MiniBooNE 6 σ No other experiments
X17 particle at 17 MeV[6] 2018 Atomki Inst. 7.2 σ Not confirmed by other experiments
W mass measurement [7] 2022 CDF 7 σ Not confirmed by other experiments
Dijets+lepton mass at 1.3 TeV [8] 2022 ATLAS 3.5 σ No CMS measurement
4-jet mass at 8 TeV [9] 2022 CMS 3.6 σ No ATLAS measurement
SUSY search [10] 2015 ATLAS 3.0 σ Not confirmed by CMS
Lepton universality in beauty-quark decays [11] 2021 LHCb 3.1 σ No other measurements
Bump at 4.8 TeV for muon+jet invariant mass using unsupervised machine learning for anomaly detection [12] 2023 ATLAS ~3 σ No other measurements
Diboson excess for ZW channel [13] 2021 ATLAS 3.4 σ CMS does not confirm
Like-sign dimuon charge asymmetry [14] 2010 D0 3.2 σ CDF does not confirm
Faster-than-light neutrino [15] 2011 OPERA 6 σ Not confirmed
2 b-quarks+1 photon [16] 1986 CDF 4 σ Not confirmed
Excess for W + 2-jets at 140 GeV [17] 2011 CDF 3.2 σ D0 does not confirm
Higgs-like excess at 114 GeV [18] 2010 ALEPH 3.2 σ No in other LEP experiments
pK0 mass at 1.52 GeV[19] 2004 ZEUS 3.9 σ H1 does not confirm
Charm pentaquark 3.1 GeV [20] 2004 H1 6.2 σ ZEUS does not confirm
nK+ mass at 1.54 GeV [21] 2003 SAPHIR 4.8 σ Not confirmed
nK+ mass at 1.54 GeV [22] 2003 LEPS/SPring-8 4.6 σ Not confirmed
pK0 mass at 1.53 GeV [23] 2003 DIANA 4.4 σ Not confirmed
Excess of deuterons in ep[24] 2007 ZEUS 10 σ or more [25] No other experiments




References

  1. ↑ M. Ablikim at al, (BES Collaboration), Study of the resonance structures in e+e−→π+π−J/ψ process URL
  2. ↑ G. Aad et al. (ATLAS Collaboration), Phys. Rev.D. 105, 012006 (2022), URL
  3. ↑ B. Abi et al. (Muon g − 2 Collaboration), Phys. Rev. Lett. 126, 141801 (2021), URL
  4. ↑ E. Aprile (XENON Collaboration), Phys. Rev. D 102, 072004 (2020) (2020), URL
  5. ↑ A.A. Aguilar-Arevalo, MiniBooNE Collaboration, Phys. Rev. Lett. 121, 221801 (2018), URL
  6. ↑ A.J. Krasznahorkay et al. nucl-ex arXiv:1910.10459 (2019) URL
  7. ↑ T. Aaltonen et al. (CDF Collaboration), Science 376, 170 URL
  8. ↑ Aad et al. (ATLAS Collaboration), ATLAS-CONF-2022-048, URL
  9. ↑ CMS Collaboration, CMS-EXO-21-010, CERN-EP-2022-103, URL
  10. ↑ ATLAS Collaboration, Eur. Phys. J. C 75 (2015) 318 URL
  11. ↑ LHCb Collaboration, HCb-PAPER-2021-004, CERN-EP-2021-042 URL
  12. ↑ ATLAS Collaboration, CERN-EP-2023-112[ https://arxiv.org/abs/2307.01612 URL]
  13. ↑ ATLAS Collaboration, JHEP 12 (2015) 55 URL
  14. ↑ D0 Collaboration, Phys.Rev. D82, 032001, 2010, URL
  15. ↑ T.Adam, (OPERA Collaboration), arXiv:1109.4897 URL
  16. ↑ CDF, [https:// URL]
  17. ↑ CDF Collaboration, Phys. Rev. Lett. 106, 171801 (2011), URL
  18. ↑ ALEPH Collaboration, Phys.Lett. B495, 1-17, 2000 URL
  19. ↑ S.Chekanov et al, (ZEUS Collaboration), Phys.Lett. B591, 7-22, 2004 URL
  20. ↑ S.Chekanov et al, (H1 Collaboration), Phys.Lett. B588, 17,2004 URL
  21. ↑ J. Barth, et al, (SAPHIR Collaboration), Phys.Lett. B572 127-132, 2003 URL
  22. ↑ T. Nakano et al. (LEPS Collaboration), Phys. Rev. Lett. 91 (2003) 012002 URL
  23. ↑ V.V. Barmin et al, (DIANA Collaboration), Phys.Atom.Nucl. 66 , 1715-1718,2003; Yad.Fiz.66:1763-1766,2003 URL
  24. ↑ S.Chekanov et al, (ZEUS Collaboration), Nucl.Phys. B786 181-205, 2007 URL
  25. ↑ Comment: There are no model predictions. The "sigma" was estimated from the deviation of the deuteron/anti-deuteron ratio from 1 (listed in the paper). This discrepancy is assumed from the fact that there should be no baryon-antibaryon asymmetry in the central fragmentation region of ep, therefore, the ratio deuteron/anti-deuteron=1 is expected. This paper confirms the expected p/anti(p)=1, but this does not hold for deuterons.
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