.
We study the imaginary parts of the isoscalar electromagnetic and isovector axial form factors of the nucleon close to the
3
π
-threshold in covariant baryon chiral perturbation theory. At the ...two-loop level, the contributions arising from leading and next-to-leading order chiral
π
N
-vertices, as well as pion-induced excitations of virtual
Δ
(
1232
)
-isobars, are calculated. It is found that the heavy baryon treatment overestimates substantially these
3
π
-continua. From a phenomenological analysis, that includes the narrow
ω
(
783
)
-resonance or the broad
a
1
-resonance, one can recognize small windows near threshold, where chiral
3
π
-dynamics prevails. However, in the case of the isoscalar electromagnetic form factors
G
E
,
M
s
(
t
)
, the radiative correction provided by the
π
0
γ
-intermediate state turns out to be of similar size.
We present a global analysis of leptonic and semileptonic kaon decay data, including all recent results published by the BNL-E865, KLOE, KTeV, ISTRA+ and NA48 experiments. This analysis, in ...conjunction with precise lattice calculations of the hadronic matrix elements now available, leads to a very precise determination of |
V
us
| and allows us to perform several stringent tests of the Standard Model.
We present a global analysis of leptonic and semileptonic kaon decay data, including all recent results published by the BNL-E865, KLOE, KTeV, ISTRA+ and NA48 experiments. This analysis, in ...conjunction with precise lattice calculations of the hadronic matrix elements now available, leads to a very precise determination of |Vus| and allows us to perform several stringent tests of the Standard Model.
Investigation at a
φ
-factory can shed light on several debated issues in particle physics. We discuss: (i) recent theoretical development and experimental progress in kaon physics relevant for the ...Standard Model tests in the flavor sector, (ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled-kaon states, (iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and
η
/
η
′ mesons, (iv) the contribution to understand the nature of light scalar mesons, and (v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the
e
+
e
−
physics in the continuum with the measurements of (multi)hadronic cross sections and the study of
γ
γ
processes.
Workshop summary: Kaons@CERN 2023 Anzivino, G.; Cuendis, Sergio Arguedas; Bernard, V. ...
The European physical journal. C, Particles and fields,
04/2024, Letnik:
84, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Kaon physics is at a turning point – while the rare-kaon experiments NA62 and KOTO are in full swing, the end of their lifetime is approaching and the future experimental landscape needs to be ...defined. With HIKE, KOTO-II and LHCb-Phase-II on the table and under scrutiny, it is a very good moment in time to take stock and contemplate about the opportunities these experiments and theoretical developments provide for particle physics in the coming decade and beyond. This paper provides a compact summary of talks and discussions from the Kaons@CERN 2023 workshop, held in September 2023 at CERN.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The standard model can be interpreted as the leading order of a Low-Energy Effective Theory (LEET) invariant under a higher non linearly realized symmetry Snat ⊃ SU(2)W × U(1)Y equipped with a ...systematic power counting. Within the minimal version of this ``not quite decoupling'' LEET, the dominant non-standard effect appears at next-to-leading order (NLO) and is a modification of the couplings of fermions to W and Z. In particular, the coupling of right-handed quarks to Z is modified and a direct coupling of right-handed quarks to W emerges. Charged right-handed lepton currents are forbidden by an additional discrete symmetry in the lepton sector originally designed to suppress Dirac neutrino masses. A complete NLO analysis of experimental constraints on these modified couplings is presented. Concerning couplings of light quarks, the interface of the electroweak tests with QCD aspects is discussed in detail.
Lorentz- and CPT-violating effects initiating two-body electromagnetic flavor-changing decays of charged leptons are studied in the framework of Lorentz-violating effective field theory. An analysis ...of data from experiments at the Paul Scherrer Institute and at the Stanford Linear Accelerator measuring the branching ratios of these decays provides 576 constraints on independent flavor-changing effects in the charged-lepton sector, consistent with no Lorentz and CPT violation at the level of parts in \(10^{-13}\) GeV\(^{-1}\) to \(10^{-9}\) GeV\(^{-1}\).
We study the imaginary parts of the isoscalar electromagnetic and isovector axial form factors of the nucleon close to the \(3\pi\)-threshold in covariant baryon chiral perturbation theory. At the ...two-loop level, the contributions arising from leading and next-to-leading order chiral \(\pi N\)-vertices, as well as pion-induced excitations of virtual \(\Delta(1232)\)-isobars, are calculated. It is found that the heavy baryon treatment overestimates substantially these \(3\pi\)-continua. From a phenomenological analysis, that includes the narrow \(\omega(783)\)-resonance or the broad \(a_1\)-resonance, one can recognize small windows near threshold, where chiral \(3\pi\)-dynamics prevails. However, in the case of the isoscalar electromagnetic form factors \(G_{E,M}^s(t)\), the radiative correction provided by the \(\pi^0\gamma\)-intermediate state turns out to be of similar size.
The Belle II Physics Book Kou, E; Beneke, M; Crivellin, A ...
Progress of theoretical and experimental physics,
12/2019, Letnik:
2019, Številka:
12
Journal Article
Recenzirano
Odprti dostop
We present the physics program of the Belle II experiment, located on the intensity frontier SuperKEKB e+e- collider. Belle II collected its first collisions in 2018, and is expected to operate for ...the next decade. It is anticipated to collect 50/ab of collision data over its lifetime. This book is the outcome of a joint effort of Belle II collaborators and theorists through the Belle II theory interface platform (B2TiP), an effort that commenced in 2014. The aim of B2TiP was to elucidate the potential impacts of the Belle II program, which includes a wide scope of physics topics: B physics, charm, tau, quarkonium, electroweak precision measurements and dark sector searches. It is composed of nine working groups (WGs), which are coordinated by teams of theorist and experimentalists conveners: Semileptonic and leptonic B decays, Radiative and Electroweak penguins, phi_1 and phi_2 (time-dependent CP violation) measurements, phi_3 measurements, Charmless hadronic B decay, Charm, Quarkonium(like), tau and low-multiplicity processes, new physics and global fit analyses. This book highlights "golden- and silver-channels", i.e. those that would have the highest potential impact in the field. Theorists scrutinised the role of those measurements and estimated the respective theoretical uncertainties, achievable now as well as prospects for the future. Experimentalists investigated the expected improvements with the large dataset expected from Belle II, taking into account improved performance from the upgraded detector.
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