Axion-like particle (ALP) portal freeze-in dark matter confronting ALP search experiments

The axion-like particle (ALP) may induce flavor-changing neutral currents (FCNCs) when the fermions’ Peccei-Quinn charges are not generation universal. The search for flavor-violating ALP couplings with a bottom quark so far focused on FCNC processes of B mesons at low energies. The recent measurements of B → K + X rare decays place stringent bounds on the quark flavor violations of a light ALP in different decay modes. In this work we propose a novel direct search for bottom flavor-violating interaction of a heavy ALP at the LHC and its upgrades, namely QCD production of an ALP associated with one b jet and one light jet p p → b j a. We consider the decay of the ALP to photons, muons and invisible ALP decays. The Boosted Decision Tree (BDT) algorithm is used to analyze the events and we train the BDT classifier by feeding in the kinematic observables of signal and backgrounds. Finally, we show the complementarity between the search prospects of hadron colliders and the low-energy B meson constraints from B meson mixing and B meson decays to a light ALP.

“…For instance, refs. [89,90] proposed the ALP portal to freeze-in dark matter. BaBar obtained an upper limit on invisible B d decays [91] BR(B d → inv) ≤ 2.4 × 10 −5…”

Section: Leptonic B Meson Decaysmentioning

confidence: 99%

The quark flavor-violating ALPs in light of B mesons and hadron colliders

Li,

Qian,

Schmidt

et al. 2024

“…ALPs are a special class of pseudo-Goldstone bosons, and ALP-SMEFT effective couplings are well-studied previously [118][119][120][121][122][123][124][125][126][127][128]. However, those studies concentrate on the lowest level interactions (mostly dim-5 operators, some also include the only one dim-6 operator), how to identify the non-redundant operators, operator transformation between different bases, oneloop corrections to these couplings, and the corresponding collider signatures.…”

Section: Introductionmentioning

confidence: 99%

Effective field theories of axion, ALP and dark photon

Song,

Sun,

2024

With the help of Young tensor technique, we enumerate the complete and independent set of effective operators up to dim-8 for the extension of the standard model with a Goldstone boson by further imposing the Adler’s zero condition in the soft momentum limit. Such basis can be reduced to describe the axion or majoron effective Lagrangian if further (symmetry) constraints are imposed. Then reformulating dark photon as combination of Goldstone boson and transverse gauge boson, the effective operators of the Goldstone boson can be extended to effective chiral Lagrangian description of the dark photon. For the first time we obtain 0 (0), 6 (44), 1 (1), 44 (356), 32 (520) operators in Goldstone effective field theory, and 9 (49), 0 (0), 108 (676), 10 (426), 1904 (40783) operators in dark photon effective field theory at the dimension 4, 5, 6, 7, 8 for one (three) generation of fermions.

Probing axion-like particles at the Electron-Ion Collider

Balkin,

Hen,

et al. 2024

The Electron-Ion Collider (EIC), a forthcoming powerful high-luminosity facility, represents an exciting opportunity to explore new physics. In this article, we study the potential of the EIC to probe the coupling between axion-like particles (ALPs) and photons in coherent scattering. The ALPs can be produced via photon fusion and decay back to two photons inside the EIC detector. In a prompt-decay search, we find that the EIC can set the most stringent bound for ma ≲ 20 GeV and probe the effective scales Λ ≲ 105 GeV. In a displaced-vertex search, which requires adopting an EM calorimeter technology that provides directionality, the EIC could probe ALPs with ma ≲ 1 GeV at effective scales Λ ≲ 107 GeV. Combining the two search strategies, the EIC can probe a significant portion of unexplored parameter space in the 0.2 < ma < 20 GeV mass range.