Search for Long-Lived Heavy Neutral Leptons with Lepton Flavour Conserving or Violating Decays to a Jet and a Charged Lepton

Hayrapetyan, Aram; Tumasyan, Armen; Adam, Wolfgang; Andrejkovic, Janik Walter; Bergauer, Thomas; Chatterjee, Suman; Damanakis, Konstantinos; Dragicevic, Marko; Hussain, Priya Sajid; Jeitler, Manfred

doi:10.1007/JHEP03(2024)105

Search for Long-Lived Heavy Neutral Leptons with Lepton Flavour Conserving or Violating Decays to a Jet and a Charged Lepton

CMS

Collaboration

Dec 12, 2023

47 pages

Published in:

JHEP 03 (2024) 105

Published: Mar 19, 2024

e-Print:

2312.07484 [hep-ex]

DOI:

10.1007/JHEP03(2024)105

Report number:

CMS-EXO-21-013,
CERN-EP-2023-256

Experiments:

CERN-LHC-CMS,
CERN-LHC-CMS

View in:

datasets

reference search23 citations

Citations per year

Abstract: (Springer)

A search for long-lived heavy neutral leptons (HNLs) is presented, which considers the hadronic final state and coupling scenarios involving all three lepton generations in the 2–20 GeV HNL mass range for the first time. Events comprising two leptons (electrons or muons) and jets are analyzed in a data sample of proton-proton collisions, recorded with the CMS experiment at the CERN LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb

^{−1}

. A novel jet tagger, based on a deep neural network, has been developed to identify jets from an HNL decay using various features of the jet and its constituent particles. The network output can be used as a powerful discriminating tool to probe a broad range of HNL lifetimes and masses. Contributions from background processes are determined from data. No excess of events in data over the expected background is observed. Upper limits on the HNL production cross section are derived as functions of the HNL mass and the three coupling strengths V

_{ℓN}

to each lepton generation ℓ and presented as exclusion limits in the coupling-mass plane, as lower limits on the HNL lifetime, and on the HNL mass. In this search, the most stringent limit on the coupling strength is obtained for pure muon coupling scenarios; values of |

{V}_{\mu \textrm{N}}^2

| > 5 (4) × 10

^{−7}

are excluded for Dirac (Majorana) HNLs with a mass of 10 GeV at a confidence level of 95% that correspond to proper decay lengths of 17 (10) mm.[graphic not available: see fulltext]

Note:

Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/EXO-21-013 (CMS Public Pages)

Beyond Standard Model
Hadron-Hadron Scattering
Lifetime
p p: colliding beams
lepton: flavor
final state: hadronic
muon: coupling
p p: scattering
neutrino: heavy
decay: length

References(81)

Figures(34)

Evidence for oscillation of atmospheric neutrinos

Super-Kamiokande

Collaboration

•

Y. Fukuda
(
- Tokyo U., ICRR
)

et al.

- Phys.Rev.Lett. 81 (1998) 1562-1567
•
e-Print:
- hep-ex/9807003
•
DOI:
- 10.1103/PhysRevLett.81.1562

Direct evidence for neutrino flavor transformation from neutral current interactions in the Sudbury Neutrino Observatory

SNO

Collaboration

•

Q.R. Ahmad

et al.

- Phys.Rev.Lett. 89 (2002) 011301
•
e-Print:
- nucl-ex/0204008
•
DOI:
- 10.1103/PhysRevLett.89.011301

[3]

Global analysis of three-flavour neutrino oscillations: synergies and tensions in the determination of $\theta_{23}$ , $\delta_{CP}$ , and the mass ordering

Ivan Esteban
(
- Barcelona U. and
- ICC, Barcelona U.
)
,
M.C. Gonzalez-Garcia
(
- Barcelona U. and
- ICC, Barcelona U. and
- ICREA, Barcelona and
- YITP, Stony Brook
)
,
Alvaro Hernandez-Cabezudo
(
- KIT, Karlsruhe
)
,
Michele Maltoni
(
- Madrid, Autonoma U.
)
,
Thomas Schwetz
(
- KIT, Karlsruhe, IPE
)

- JHEP 01 (2019) 106
•
e-Print:
- 1811.05487
•
DOI:
- 10.1007/JHEP01(2019)106

Direct neutrino-mass measurement with sub-electronvolt sensitivity

KATRIN

Collaboration

•

M. Aker
(
- KIT, Karlsruhe and
- KIT, Karlsruhe, IAP
)

et al.

- Nature Phys. 18 (2022) 2, 160-166
•
e-Print:
- 2105.08533
•
DOI:
- 10.1038/s41567-021-01463-1

Review of Particle Physics

R.L. Workman
(
- George Washington U.
)
,
V.D. Burkert
(
- Jefferson Lab
)
,
V. Crede
(
- Florida State U.
)
,
E. Klempt
(
- Bonn U., HISKP
)
,
U. Thoma
(
- Bonn U., HISKP
)

et al.

- PTEP 2022 (2022) 083C01
•
DOI:
- 10.1093/ptep/ptac097

[6]

$\mu \to e\gamma$ at a Rate of One Out of $10^{9}$ Muon Decays?

Peter Minkowski
(
- Bern U.
)

- Phys.Lett.B 67 (1977) 421-428
•
DOI:
- 10.1016/0370-2693(77)90435-X

[7]

Complex Spinors and Unified Theories

- Conf.Proc.C 790927 (1979) 315-321,
- Stony Brook Wkshp.1979:0315,
- Republished in Murray Gell-Mann: Selected Papers pp.266-267
•
e-Print:
- 1306.4669