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Mediator Decay through mixing with Degenerate Spectrum (2404.06793v2)
Published 10 Apr 2024 in hep-ph
Abstract: The decay of the mediator particle into standard model (SM) particles plays a significant role in exploring the dark sector scenario. We consider such a decay, taking the dark photon mediator as an example that mixes with the SM photon. We find that it requires a careful analysis of the decay rate in the presence of an SM vector boson (e.g., $Z$ boson, $\rho$ meson, and true muonium, etc.) nearly degenerate with the mediator particle in mass. The decay rate of the mediator particle calculated in the mass eigenstate basis {\bf does not} agree with the correct result, given by the imaginary parts of the poles for the vector boson propagators, when the mixing parameter is smaller than a specific value. In such a case, the decay rate calculated by treating the mixing as a perturbative parameter is in agreement with the correct result. We clarify specific values for the mixing parameter quantitatively using several concrete examples of the SM vector bosons degenerate with the dark photon. When the mass mixing between the vector boson and dark photon is smaller (larger) than the decay width of the vector boson, the latter (former) method to calculate the decay rate of the mediator particle gives the correct result.
- A. Fradette, M. Pospelov, J. Pradler, and A. Ritz, “Cosmological Constraints on Very Dark Photons,” Phys. Rev. D 90 no. 3, (2014) 035022, arXiv:1407.0993 [hep-ph].
- A. Kamada and H.-B. Yu, “Coherent Propagation of PeV Neutrinos and the Dip in the Neutrino Spectrum at IceCube,” Phys. Rev. D 92 no. 11, (2015) 113004, arXiv:1504.00711 [hep-ph].
- M. Hufnagel, K. Schmidt-Hoberg, and S. Wild, “BBN constraints on MeV-scale dark sectors. Part II. Electromagnetic decays,” JCAP 11 (2018) 032, arXiv:1808.09324 [hep-ph].
- M. Ibe, A. Kamada, S. Kobayashi, and W. Nakano, “Composite Asymmetric Dark Matter with a Dark Photon Portal,” JHEP 11 (2018) 203, arXiv:1805.06876 [hep-ph].
- M. Ibe, S. Kobayashi, Y. Nakayama, and S. Shirai, “Cosmological constraint on dark photon from Neff𝑒𝑓𝑓{}_{eff}start_FLOATSUBSCRIPT italic_e italic_f italic_f end_FLOATSUBSCRIPT,” JHEP 04 (2020) 009, arXiv:1912.12152 [hep-ph].
- APEX Collaboration, S. Abrahamyan et al., “Search for a New Gauge Boson in Electron-Nucleus Fixed-Target Scattering by the APEX Experiment,” Phys. Rev. Lett. 107 (2011) 191804, arXiv:1108.2750 [hep-ex].
- KLOE-2 Collaboration, F. Archilli et al., “Search for a vector gauge boson in ϕitalic-ϕ\phiitalic_ϕ meson decays with the KLOE detector,” Phys. Lett. B 706 (2012) 251–255, arXiv:1110.0411 [hep-ex].
- KLOE-2 Collaboration, D. Babusci et al., “Limit on the production of a light vector gauge boson in phi meson decays with the KLOE detector,” Phys. Lett. B 720 (2013) 111–115, arXiv:1210.3927 [hep-ex].
- BaBar Collaboration, J. P. Lees et al., “Search for a Dark Photon in e+e−superscript𝑒superscript𝑒e^{+}e^{-}italic_e start_POSTSUPERSCRIPT + end_POSTSUPERSCRIPT italic_e start_POSTSUPERSCRIPT - end_POSTSUPERSCRIPT Collisions at BaBar,” Phys. Rev. Lett. 113 no. 20, (2014) 201801, arXiv:1406.2980 [hep-ex].
- LHCb Collaboration, R. Aaij et al., “Search for hidden-sector bosons in B0→K*0μ+μ−→superscript𝐵0superscript𝐾absent0superscript𝜇superscript𝜇B^{0}\!\to K^{*0}\mu^{+}\mu^{-}italic_B start_POSTSUPERSCRIPT 0 end_POSTSUPERSCRIPT → italic_K start_POSTSUPERSCRIPT * 0 end_POSTSUPERSCRIPT italic_μ start_POSTSUPERSCRIPT + end_POSTSUPERSCRIPT italic_μ start_POSTSUPERSCRIPT - end_POSTSUPERSCRIPT decays,” Phys. Rev. Lett. 115 no. 16, (2015) 161802, arXiv:1508.04094 [hep-ex].
- NA48/2 Collaboration, J. R. Batley et al., “Search for the dark photon in π0superscript𝜋0\pi^{0}italic_π start_POSTSUPERSCRIPT 0 end_POSTSUPERSCRIPT decays,” Phys. Lett. B 746 (2015) 178–185, arXiv:1504.00607 [hep-ex].
- LHCb Collaboration, R. Aaij et al., “Search for long-lived scalar particles in B+→K+χ(μ+μ−)→superscript𝐵superscript𝐾𝜒superscript𝜇superscript𝜇B^{+}\to K^{+}\chi(\mu^{+}\mu^{-})italic_B start_POSTSUPERSCRIPT + end_POSTSUPERSCRIPT → italic_K start_POSTSUPERSCRIPT + end_POSTSUPERSCRIPT italic_χ ( italic_μ start_POSTSUPERSCRIPT + end_POSTSUPERSCRIPT italic_μ start_POSTSUPERSCRIPT - end_POSTSUPERSCRIPT ) decays,” Phys. Rev. D 95 no. 7, (2017) 071101, arXiv:1612.07818 [hep-ex].
- LHCb Collaboration, R. Aaij et al., “Search for Dark Photons Produced in 13 TeV pp𝑝𝑝ppitalic_p italic_p Collisions,” Phys. Rev. Lett. 120 no. 6, (2018) 061801, arXiv:1710.02867 [hep-ex].
- NA62 Collaboration, E. Cortina Gil et al., “Search for π0superscript𝜋0\pi^{0}italic_π start_POSTSUPERSCRIPT 0 end_POSTSUPERSCRIPT decays to invisible particles,” JHEP 02 (2021) 201, arXiv:2010.07644 [hep-ex].
- NA62 Collaboration, E. Cortina Gil et al., “Measurement of the very rare K+{}^{+}start_FLOATSUPERSCRIPT + end_FLOATSUPERSCRIPT→π+νν¯superscript𝜋𝜈¯𝜈{\pi}^{+}\nu\overline{\nu}italic_π start_POSTSUPERSCRIPT + end_POSTSUPERSCRIPT italic_ν over¯ start_ARG italic_ν end_ARG decay,” JHEP 06 (2021) 093, arXiv:2103.15389 [hep-ex].
- CMS Collaboration, A. Tumasyan et al., “Search for long-lived particles decaying into muon pairs in proton-proton collisions at s𝑠\sqrt{s}square-root start_ARG italic_s end_ARG = 13 TeV collected with a dedicated high-rate data stream,” JHEP 04 (2022) 062, arXiv:2112.13769 [hep-ex].
- J. L. Feng et al., “The Forward Physics Facility at the High-Luminosity LHC,” J. Phys. G 50 no. 3, (2023) 030501, arXiv:2203.05090 [hep-ex].
- Belle-II Collaboration, I. Adachi et al., “Search for a long-lived spin-0 mediator in b→s→𝑏𝑠b\to sitalic_b → italic_s transitions at the Belle II experiment,” arXiv:2306.02830 [hep-ex].
- FASER Collaboration, H. Abreu et al., “Search for dark photons with the FASER detector at the LHC,” Phys. Lett. B 848 (2024) 138378, arXiv:2308.05587 [hep-ex].
- B. Holdom, “Two U(1)’s and Epsilon Charge Shifts,” Phys. Lett. B 166 (1986) 196–198.
- M. Bando, T. Kugo, S. Uehara, K. Yamawaki, and T. Yanagida, “Is rho Meson a Dynamical Gauge Boson of Hidden Local Symmetry?,” Phys. Rev. Lett. 54 (1985) 1215.
- M. Harada and K. Yamawaki, “Hidden local symmetry at loop: A New perspective of composite gauge boson and chiral phase transition,” Phys. Rept. 381 (2003) 1–233, arXiv:hep-ph/0302103.
- S. Matsumoto, Y. Watanabe, Y. Watanabe, and G. White, “Decay of the mediator particle at threshold,” JHEP 09 (2023) 015, arXiv:2212.10739 [hep-ph].
- A. Hook, E. Izaguirre, and J. G. Wacker, “Model Independent Bounds on Kinetic Mixing,” Adv. High Energy Phys. 2011 (2011) 859762, arXiv:1006.0973 [hep-ph].
- D. Curtin, R. Essig, S. Gori, and J. Shelton, “Illuminating Dark Photons with High-Energy Colliders,” JHEP 02 (2015) 157, arXiv:1412.0018 [hep-ph].
- E. Izaguirre, G. Krnjaic, and B. Shuve, “Discovering Inelastic Thermal-Relic Dark Matter at Colliders,” Phys. Rev. D 93 no. 6, (2016) 063523, arXiv:1508.03050 [hep-ph].
- E. Izaguirre, Y. Kahn, G. Krnjaic, and M. Moschella, “Testing Light Dark Matter Coannihilation With Fixed-Target Experiments,” Phys. Rev. D 96 no. 5, (2017) 055007, arXiv:1703.06881 [hep-ph].
- A. Berlin and F. Kling, “Inelastic Dark Matter at the LHC Lifetime Frontier: ATLAS, CMS, LHCb, CODEX-b, FASER, and MATHUSLA,” Phys. Rev. D 99 no. 1, (2019) 015021, arXiv:1810.01879 [hep-ph].
- J. D. Bjorken, R. Essig, P. Schuster, and N. Toro, “New Fixed-Target Experiments to Search for Dark Gauge Forces,” Phys. Rev. D 80 (2009) 075018, arXiv:0906.0580 [hep-ph].
- J. Blümlein and J. Brunner, “New Exclusion Limits on Dark Gauge Forces from Proton Bremsstrahlung in Beam-Dump Data,” Phys. Lett. B 731 (2014) 320–326, arXiv:1311.3870 [hep-ph].
- A. Berlin, S. Gori, P. Schuster, and N. Toro, “Dark Sectors at the Fermilab SeaQuest Experiment,” Phys. Rev. D 98 no. 3, (2018) 035011, arXiv:1804.00661 [hep-ph].
- P. Ilten, Y. Soreq, M. Williams, and W. Xue, “Serendipity in dark photon searches,” JHEP 06 (2018) 004, arXiv:1801.04847 [hep-ph].
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