Precision measurement of thee+e−→K+K−(γ

Abstract

A precise measurement of the cross section for the process e + e − → K + K − (γ) from threshold to an energy of 5 GeV is obtained with the initial-state radiation (ISR) method using 232 fb −1 of data collected with the BABAR detector at e + e − center-of-mass energies near 10.6 GeV. The measurement uses the effective ISR luminosity determined from the e + e − → µ + µ − (γ)γISR process with the same data set. The corresponding lowest-order contribution to the hadronic vacuum polarization term in the muon magnetic anomaly is found to be a KK,LO µ = (22.93 ± 0.18stat ± 0.22syst) × 10 −10 . The charged kaon form factor is extracted and compared to previous results. Its magnitude at large energy significantly exceeds the asymptotic QCD prediction, while the measured slope is consistent with the prediction.

Coupling QCD-Scale Axionlike Particles to Gluons

“…We define these as: (ω-like) above where the sizable ωφ interference effect in the 3π final state becomes negligible, (ρ-like) ma mρ * + Γρ * , and (φ-like) ma m φ * + Γ φ * .where β F = 1.4 GeV is determined from the data. Furthermore, in the Supplemental Material we show that all e + e − → V → P P data [37,38] are also consistent with Eq. (17), modulo the pQCD power-law scaling is m −3 due to the dimensionality of the VMD-based V P P vertex.…”

Cross sections for the reactions e+e−→KS0Lees1, Poireau2, Tisserand3 et al. 2017Phys. Rev. DSelf Cite19090View full textAdd to dashboardCite

“…We also search for the e þ e − → γK 0 S K 0 S π 0 and e þ e − → γK 0 S K 0 S π 0 π 0 processes, which are forbidden by C-parity conservation, and we see no indication of them at the level of single background events. Together with our previous measurements [8,11,16], these results provide a much more complete understanding of the KKπ, KKη and KKππ final states in e þ e − annihilation.…”

“…The X h studied so far include charged hadron pairs π þ π − [7], [8], and pp [9]; four or six charged mesons [10][11][12]; charged mesons plus one or two π 0 mesons [11][12][13][14]; a K 0 S plus charged and neutral mesons [15]; and the first ISR measurement from BABAR that includes K 0 L mesons [16]. Together, they demonstrate good detector efficiency for events of this kind and well-understood tracking, particle identification, and π 0 , K For these final states, we measure cross sections from threshold to E c:m: ¼ 4 GeV, study their internal structure, perform the first measurements of J=ψ branching fractions, and search for ψð2SÞ decays.…”

WG4 Highlights: QCD and Hadronic Final States

“…The BaBar Collaboration has reported on measurements of light meson production cross sections, π + π − (γ) and K + K − (γ), in e + e − collisions at SLAC ( √ s = 10.58 GeV) [69,70,71,72]. The cross sections are measured by identifying events with a photon radiated in the initial state with E * γ > 3 GeV which effectively lowers the center-of-mass energy of the hard process from threshold to up to √ s = 3 to 5 GeV.…”