Constraints on light scalars from PS191 results

Scale Invariant FIMP Miracle

“…We find, in order to satisfy bounds from relic density, spin-independent direct detection and big bang nucleosynthesis (BBN), the mixing within the scalar sector has to be sin θ ∼ g X ∼ O(10 −5 ). Such a mixing angle is indeed within the reach of experiments like DUNE [117,118], FASER-II [119][120][121][122], PS191 [123,124], DarkQuest-Phase2 [125], MATHUSLA [126] and SHiP [127]. Most importantly, since the mixing θ is no more a free parameter (due to the scale invariance of the theory), it rather can be parametrized in terms of m X and g X , hence, the new gauge coupling that determines the freeze-in abundance, is directly being probed at plethora of 4 We have used the two terms "scale" invariance and "conformal" invariance interchangeably in this paper since they are known to be classically equivalent in any four-dimensional unitary and renormalizable field theory [111][112][113].…”

Search for a light Higgs boson in single-photon decays of $Υ(1S)$ using $Υ(2S) \to π^+ π^- Υ(1S)$ tagging method

“…FIG.5: The surviving parameter space on the plane of sinθ A 0 and m A 0 . The constraints from LEP[52] (direct production of Higgs), BESIII[53] (J/ψ decay), Belle (Υ(1S) decay), LHCb[54,55] (B +/0 decay), NA62[56][57][58] (K + decay), KTeV[13,59,60] (KL decay), CHARM[13,[61][62][63][64] (beam dump), PS191[65] (beam dump), SN1987A[66], BBN[67], and the prospect of future SHiP[13,64] (beam dump) are shown.…”

Revisiting PS191 limits on sterile neutrinos

“…We estimate the expected number of HNL signal events in the PS191 detector by making use of the Monte Carlo simulations of the kaon production by N sim = 2 × 10 6 protons of energy 19.2 GeV, which we have performed in Ref. [12] for investigation of PS191 sensitivity to hypothetical light scalars. The kaon production, further propagation and scattering in the target, decay tunnel (walls) and iron dump till the weak decay have been simulated with GEANT4 toolkit [13] with BERTini and QGSP models utilized for low and high energy strong interactions respectively.…”

“…Many details (numbers, particle distributions over momenta and decay points, etc) of the simulations can be found in Ref. [12]. We accounted for the secondary kaon production in the tunnel walls, iron dump and soil (we approximated it as sand).…”

“…Say, in the first interaction the incident proton produces about 0.065 K + and 0.032 K − , see Tab. 1 in [12] for the total kaon budget. We use those simulated K − for both "on"and "off"-modes as we argued above.…”