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Home  ⪧  Research  ⪧  Particle Physics  ⪧  KLOE2

KLOE2

The main goal of the KLOE/KLOE-2 experiment is the precision study of ϕ(1020) meson decays into neutral and charged Kaons, and the scalar and pseudoscalar mesons below 1 GeV. Of particular interest are: precise measurement of the CKM element V_us , tests of the discrete symmetries of the nature and the study of the structure of the scalar states. The coherent propagation of neutral Kaon pairs is sensitive to modifications of Quantum Mechanics and CPT-invariance at the Planck scale. Also the processes from the continuum, with the precision measurements of the hadronic cross section, σ(e⁺e⁻→π⁺π⁻γ), and the study of γγ interactions, are part of the research program.

The total integrated luminosity delivered by the e⁺e⁻ collider DAΦNE to KLOE in the first phase of data-taking, ended in 2006, is about 2.5 fb^-1. After the insertion of a new interaction region in DAΦNE to increase the machine luminosity, a new data-taking campaign started in November 2014 with an upgraded detector, to increase statistics. The second phase of data-taking ended in March 2018 with the collection of 5.5 fb^-1 of data. This sample together with the KLOE data constitutes the largest sample ever collecteted at the peak of the ϕ(1020) resonance (about 24 billions of ϕ mesons produced).

The list of physics topics, which are described in details in the paper Eur.Phys.J. C68 (2010) 619, includes:

• Rare K_S decays, such as K_S→πeν, or the CP--forbidden K_S→3π⁰ decay;
• Precision measurements of K_L and charged Kaons branching ratios and lifetimes;
• Precision measurement of the V_us element of the CKM matrix;
• Study of the quantum interference with entangled neutral Kaon pairs from ϕ decays;
• Radiative ϕ-decays and study of scalar and pseudoscalar mesons;
• Ratio R(hadrons), of interest for the theoretical calculation of the hadronic contribution to the anomalous magnetic moment of the muon;
• Study of γγ processes (e⁺e⁻→e⁺e⁻γ*γ*→e⁺e⁻X);
• Search for particles in the Dark sector (Dark Photons, Leptophobic B-Boson, Axion-Like Particles).

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Websites:

• KLOE2 International

Thesis Opportunities:

• Can the future influence the past in entangled Kaon states ?
  The entanglement of a neutral K-meson (kaon) pair shows a novel and apparently paradoxical effect "from future to past", due to the non-local nature of Quantum Mechanics, which can be observed for the first time by studying the correlations between the two Kaon decays.
• Search for decoherence effects and CPT violation in the Neutral Kaon system at KLOE/KLOE-2
  The study of the correlation of the decay times of the K mesons produced in ϕ→K_SK_L→π⁺π^-π⁺π^- is one of the most precise and refined tests of Quantum Mechanics and of the CP symmetry.
• Direct test of CPT symmetry in the transitions of entangled K mesons at KLOE/KLOE-2
  Exploiting the properties of the entangled Kaon pair produced in the decay ϕ→K_SK_L it is possible to perform the first precise test of the CPT symmetry directly in the trantisions of the K mesons.
• Study of the rare decay η→π⁰γγ with the KLOE-2 data
  Unique test of the O(p⁶) terms of Chiral Perturbation Theory.
• Study of final states produced in γγ collisions at KLOE-2
  Use of the new detectors for e^± tagging installed in KLOE-2 to detect γγ processes.
• Search for Axion-Like Particles (APLs) in γγ final states at KLOE-2
  ALPs are a generalization of the the QCD axions, but with arbitrary masses and couplings to be determined from experiments. ALPS can be scalar or pseudoscalar particles, which at the KLOE-2 energies, in the mass range 100 MeV – 1 GeV, can be produced in ϕ radiative decays or γγ processes, and detected through their decays in 2 photons.

For further information about thesis opportunities, please contact: Antonio Di Domenico, Paolo Gauzzi and Giulio D'Agostini.

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Local Coordinator

Paolo Gauzzi

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