Search for a vector gauge boson in ϕ meson decays with the KLOE detector

Archilli, F.; Babusci, D.; Badoni, D.; Balwierz, I.; Bencivenni, G.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Budano, A.; Bulychjev, S. A.; Balkeståhl, L. Caldeira; Campana, P.; Capon, G.; Ceradini, F.; Ciambrone, P.; Czerwiński, E.; Dané, E.; Lucia, E. De; Robertis, G. De; Santis, A. De; Zorzi, G. De; Domenico, A. Di; Donato, C. Di; Domenici, D.; Erriquez, O.; Fanizzi, G.; Felici, G.; Fiore, S.; Franzini, P.; Gauzzi, P.; Giardina, G.; Giovannella, S.; Gonnella, F.; Graziani, E.; Happacher, F.; Höistad, B.; Iafolla, L.; Iarocci, E.; Jacewicz, M.; Johansson, T.; Kowalewska, A. B.; Kulikov, V.; Kupść, A.; Lee‐Franzini, J.; Loddo, F.; Mandaglio, G.; Martemianov, M.; Martini, M.; Mascolo, M.; Matsyuk, M.; Messi, R.; Miscetti, S.; Morello, G.; Moricciani, D.; Moskal, P.; Nguyen, F.; Passeri, A.; Patera, V.; Longhi, I. Prado; Ranieri, A.; Redmer, C. F.; Santangelo, P.; Sarra, I.; Schioppa, M.; Sciascia, B.; Sciubba, A.; Silarski, M.; Stucci, Stefania Antonia; Taccini, C.; Tortora, L.; Venanzoni, G.; Versaci, R.; Wiślicki, W.; Wolke, M.; Zdebik, J.

doi:10.1016/j.physletb.2011.11.033

Cited by 159 publications

(163 citation statements)

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“…A search for the U boson in the φ → ηU process, with U decaying into an e + e − pair, has been performed at KLOE by analysing a data sample of 1.5 fb −1 in the case of η decaying into π + π − π 0 [9] and 1.7 fb −1 in the case of η → π 0 π 0 π 0 [8]. No evidence in the e + e − invariant mass spectrum was found for both searches [8,9].…”

Section: Search For the U Boson In Dalitz Decays Of φmentioning

confidence: 99%

“…No evidence in the e + e − invariant mass spectrum was found for both searches [8,9]. A combined and more stringent upper limit [8] at 90 % CL on the ratio between the coupling constant and the fine structure constant of α /α < 1.7 × 10 −5 for 30 < m U < 400 MeV and α /α < 8 × 10 −6 for the sub-region 50 < m U < 210 MeV was evaluated.…”

Section: Search For the U Boson In Dalitz Decays Of φmentioning

confidence: 99%

“…Moreover, search for the U boson in such energy range is of special interest as it could explain a number of recent puzzing astrophysical observations such as the excess of positrons in cosmic rays observed by AMS and PAMELA [1,2], 511 keV gamma rays from the galactic centre seen by INTEGRAL [3] or the annual modulation signal measured by DAMA/LIBRA [4]. The KLOE experiment has searched evidence of the U boson existence as a sharp resonance in the invariant mass spectrum of lepton or pion pairs produced in radiative processes e + e − → + − (γ) [5,6], e + e − → π + π − (γ) [7] and in decays of the φ meson [8,9], as well as in the dark Higgsstrahlunng process [10].…”

Section: Introductionmentioning

confidence: 99%

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Search for dark forces with KLOE

Gajos

2016

EPJ Web Conf.

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Abstract. During the last years several Dark Sector Models have been proposed in order to address striking astrophysical observations which failed standard interpretations. In the minimal case a new vector particle, the so called dark photon, or A or U boson, is introduced, with small coupling with Standard Model particles. Also, the existence of a dark Higgs boson h is postulated, in analogy with the Standard Model, to give mass to the U boson through the Spontaneous Symmetry Breaking mechanism. The KLOE experiment working at DAΦNE, an e + e − collider operating in Frascati (near Rome), searched for the existence of the U boson investigating three different processes and six different final states: (1) in Dalitz decays of the φ meson φ → ηU, with U → e + e − and η → π + π − π 0 and π 0 π 0 π 0 , (2) in e + e − → Uγ events, with U decaying into lepton and pion pairs, (3) in the dark Higgsstrahlung process, e + e − → Uh , U → μ + μ − , h invisible. Limits on the model parameters have been set at 90 % CL for U boson masses below 1 GeV. Further improvements are expected in terms of sensitivity and discovery potential with the new KLOE-2 detector.

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Section: Search For the U Boson In Dalitz Decays Of φmentioning

confidence: 99%

Section: Search For the U Boson In Dalitz Decays Of φmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Search for dark forces with KLOE

Gajos

2016

EPJ Web Conf.

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“…One dangerous instrumental background comes from photon conversions over the detector material, which is removed by properly developed software algorithms. In the two papers [8,9], KLOE did not find evidence for peaks, therefore the following limits could have been set, both at 90% CL: 2 ≤ 1.5 × 10 −5 for 30 < M U (MeV) < 420 2 ≤ 5.0 × 10 −6 for 60 < M U (MeV) < 190.…”

Section: Direct Searchesmentioning

confidence: 99%

Searches for physics beyond the Standard Model at KLOE

Bossi

2014

EPJ Web of Conferences

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Abstract. The KLOE detector, operating at the DA NE -factory facility of INFN Frascati, has contributed in several ways to the confirmation of the Standard Model, while searching at the same time for direct or indirect hints for new physics signals. Among those, I will discuss briefly the long-standing effort for the precise determination of the hadronic contribution to the muon magnetic anomaly, and the searches for a new, light, neutral vector boson.

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“…Related searches for prompt LJs have been performed both at the Tevatron [10,11] and at the LHC [12][13][14][15]. Additional constraints on scenarios with hidden photons are extracted from, e.g., beam-dump and fixed-target experiments [16,17,[17][18][19][20][21][22][23][24][25][26][27], e + e − colliders [28][29][30], B-factories [31,32], electron and muon anomalous magnetic moment measurements [33][34][35] and astrophysical observations [36,37].The properties of the LJ, such as its shape and particle multiplicity, strongly depend on the unknown structure of the hidden sector and its couplings to the visible sector. Therefore the search criteria must be as model-independent as possible, targeting the basic experimental signatures that correspond to these objects.…”

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confidence: 99%

Search for long-lived neutral particles decaying into lepton jets in proton-proton collisions at s = 8 $$ \sqrt{s}=8 $$ TeV with the ATLAS detector

Aad¹,

Abbott²,

Abdallah³

et al. 2014

J. High Energ. Phys.

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109

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Several models of physics beyond the Standard Model predict neutral particles that decay into final states consisting of collimated jets of light leptons and hadrons (socalled "lepton jets"). These particles can also be long-lived with decay length comparable to, or even larger than, the LHC detectors' linear dimensions. This paper presents the results of a search for lepton jets in proton-proton collisions at the centre-of-mass energy of √ s = 8 TeV in a sample of 20.3 fb −1 collected during 2012 with the ATLAS detector at the LHC. Limits on models predicting Higgs boson decays to neutral long-lived lepton jets are derived as a function of the particle's proper decay length. An extensively studied case is one in which the two sectors couple via the vector portal, in which a light hidden photon (dark photon, γ d ) mixes kinetically with the SM photon. If the hidden photon is the lightest state in the hidden sector, it decays back to SM particles with branching fractions that depend on its mass [6,8,9]. For the case in which the γ d kinetically mixes with hypercharge, one finds that , the kinetic mixing parameter, controls -1 - Keywords: Hadron-Hadron Scattering JHEP11(2014)088both the γ d decay branching fractions and lifetime. More generally, however, the branching fractions and lifetime are model-dependent and may depend on additional parameters.Due to their small mass, these particles are typically produced with a large boost and, due to their weak interactions, can have non-negligible lifetime. As a result one may expect, from dark photon decays, collimated jet-like structures containing pairs of electrons and/or muons and/or charged pions ("lepton jets", LJs) that can be produced far from the primary interaction vertex of the event (displaced LJs).Neutral particles which decay far from the interaction point into collimated final states represent a challenge both for the trigger and for the reconstruction capabilities of the LHC detectors. Collimated charged particles in the final state can be difficult to disentangle due to the limited granularity of the detector. Moreover, in the absence of information from the inner tracking system, it is necessary to use the muon spectrometer (MS) for the reconstruction of tracks which originate from a secondary decay far from the primary interaction vertex (IP).The high-resolution, high-granularity measurement capability of the ATLAS "air-core" MS is ideal for this type of search. In addition, the ATLAS inner tracking system can be used to define isolation criteria to significantly reduce, for decay vertices far from the interaction point, the otherwise overwhelming SM background from proton-proton collisions.The search for displaced LJs presented in this paper employs the full dataset collected by ATLAS during the 2012 run at √ s = 8 TeV, corresponding to an integrated luminosity of 20.3 fb −1 . Related searches for prompt LJs have been performed both at the Tevatron [10,11] and at the LHC [12][13][14][15]. Additional constraints on scenarios with hidden phot...

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Search for a vector gauge boson in ϕ meson decays with the KLOE detector

Cited by 159 publications

References 44 publications

Search for dark forces with KLOE

Search for dark forces with KLOE

Searches for physics beyond the Standard Model at KLOE

Search for long-lived neutral particles decaying into lepton jets in proton-proton collisions at s = 8 $$ \sqrt{s}=8 $$ TeV with the ATLAS detector

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