Neutral pion form factor measurement by the NA62 experiment

M Zamkovsky ,S Gallorini ,M Koval ,A Winhart ,A Nappi ,B Peyaud ,M Holder ,G Bocquet ,M Napolitano ,N Doble ,G Dellacasa ,M Szleper ,D Cundy ,M Jeitler ,A Peters ,C Biino ,M Velasco ,I Mikulec ,A Maier ,H Wahl ,P Riedler ,A Walker ,A Norton ,G Kalmus ,D Madigozhin ,N Lurkin ,M Piccini ,J Engelfried ,N Cartiglia ,V Palladino ,V Kekelidze ,G Pierazzini ,E Goudzovski ,F Petrucci ,S Stoynev ,James B Derr ,A Dabrowski ,C Cerri ,Max Wood ,S Bifani ,E Gersabeck ,A Romano ,A Bizzeti ,A Sergi ,C Cheshkov ,L Fiorini ,L Litov ,R Piandani ,M W Slater ,V Semenov ,D.j Munday ,T Fonseca Martin ,В.н Болотов ,M Calvetti ,J R Batley ,E Monnier ,M Valdata‐Nappi ,T Blažek ,I Popov ,P Massarotti ,A Zinchenko ,N Cabibbo ,E Leonardi ,G D’agostini ,P Hristov ,M Misheva ,N Molokanova ,V Duk ,P Dalpiaz ,R Arcidiacono ,D Coward ,M Clemencic ,R Wanke ,R Winston ,M C Petrucci ,K Kleinknecht ,M Raggi ,M Pepé ,M De Beer ,U Moosbrugger ,F Bucci ,G Marel ,S Giudici ,M Wache ,G Neuhofer ,M Fidecaro ,A Gonidec ,A Fucci ,V Kurshetsov ,I Polenkevich ,M Behler ,R Fantechi ,M Sozzi ,C Damiani ,E Mazzucato ,G Ruggiero ,M Savri ,E C Swallow ,M Shieh ,E Iacopini ,A Gianoli ,S A Wotton ,L Gatignon ,M Fiorini ,I Mannelli ,G Lamanna ,H Dibon ,M Scarpa ,G Anzivino ,A Ceccucci ,T Spadaro ,C Morales Morales ,A Cotta Ramusino ,L Masetti ,V Falaleev ,B Hallgren ,A Antonelli ,L Widhalm ,M Hita-Hochgesand ,M Serra ,M Martini ,O Yushchenko ,M Patel ,W Kubischta ,A Salamon ,S Movchan ,M Markytan ,S Goy Lopez ,B Bloch-Devaux ,P Marouelli ,V Obraztsov ,P Valente ,F Costantini ,E Imbergamo ,A Michetti ,B Vallage ,S Shkarovskiy ,G Saracino ,H O Danielsson ,L Dilella ,T Numao ,K Eppard ,C Lazzeroni ,M Veltri ,P L Frabetti ,F Ambrosino ,D Di Filippo ,M Moulson ,Yu Potrebenikov ,F Marchetto ,W Baldini ,P Cenci ,V Kozhuharov ,E Gushchin ,P Rubin ,S Balev ,B Renk ,F Retire ,M Lenti ,G Collazuol ,S Venditti ,J B Chze ,M Ziolkowski

doi:10.1088/1742-6596/873/1/012016

M Zamkovsky , S Gallorini + Show 161 more

Open Access

https://doi.org/10.1088/1742-6596/873/1/012016

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Abstract

The NA62 experiment at CERN collected a large sample of charged kaon decays with a highly efficient trigger for decays into electrons in 2007. The kaon beam represents a source of tagged neutral pion decays in vacuum. A measurement of the electromagnetic transition form factor slope of the neutral pion in the time-like region from ∼1 million fully reconstructed π0 Dalitz decay is presented. The limits on dark photon production in π0 decays from the earlier kaon experiment at CERN, NA48/2, are also reported.

Highlights

The NA48/2 experiment at the CERN SPS recorded a sample of 2 × 1011 charged kaon decays in 2003-04
This paper reports on the measurements of neutral pion physics on NA62 and NA48/2, namely the measurement of the slope of the π0 electromagnetic transition form factor from a sample of π0 → e+e−γ decays and the search for the dark photon in the π0 → γA decay
The fiducial region was followed by a magnetic spectrometer, consisting of four drift chambers (DCH), housed in a vessel filled with helium gas at nearly atmospheric pressure

Summary

Introduction

The NA48/2 experiment at the CERN SPS recorded a sample of 2 × 1011 charged kaon decays in 2003-04. The following NA62 experiment collected a ten times smaller sample of K± in 2007 and was using the NA48 detector [1] and a modified beam line [2]. The fiducial region was followed by a magnetic spectrometer, consisting of four drift chambers (DCH), housed in a vessel filled with helium gas at nearly atmospheric pressure. The spectrometer was followed by a scintillator hodoscope consisting of two planes segmented into horizontal and vertical strips achieving a very good ∼ 150 ps time resolution. In the allowed kinematic region for the πD0 decay, F (x) is expected to vary slowly and it is sufficient to use a linear approximation F (x) = 1 + ax, where a is the so-called π0 transition f orm f actor (TFF) slope parameter. The comparison of TFF slope predictions with a model independent measurement is an important test of the theory models

Radiative Corrections

Search for the dark photon

Conclusion