Search for a positron anisotropy with PAMELA experiment
B. Panico1,O. Adriani3,4,G. C. Barbarino1,2,G. A. Bazilevskaya5,R. Bellotti6,7,M. Boezio8,E. A. Bogomolov9,M. Bongi3,4,V. Bonvicini8,S. Bottai4,A. Bruno6,F. Cafagna7,D. Campana1,P. Carlson10,M. Casolino11,12,G. Castellini13,C. De Donato11,14,C. De Santis11,14,N. De Simone11,V. Di Felice11,15,V. Formato8,16,A. M. Galper17,U. Giaccari4,a,A. V. Karelin17,S. V. Koldashov17,S. Koldobskiy17,S. Y. Krutkov9,A. N. Kvashnin5,A. Leonov17,V. Malakhov17,L. Marcelli11,14,M. Martucci14,18,A. G. Mayorov17,W. Menn19,M. Mergé11,14,V. V. Mikhailov17,E. Mocchiutti8,A. Monaco6,7,N. Mori3,4,R. Munini8,16,G. Osteria1,F. Palma11,14,M. Pearce10,P. Picozza11,14,M. Ricci18,S. B. Ricciarini4,13,R. Sarkar8,b,V. Scotti1,2,M. Simon19,R. Sparvoli11,14,P. Spillantini3,4,Y. I. Stozhkov5,A. Vacchi8,E. Vannuccini4,G. I. Vasilyev9,S. A. Voronov17,Y. T. Yurkin17,G. Zampa8,and N. Zampa8B. Panico et al.B. Panico1,O. Adriani3,4,G. C. Barbarino1,2,G. A. Bazilevskaya5,R. Bellotti6,7,M. Boezio8,E. A. Bogomolov9,M. Bongi3,4,V. Bonvicini8,S. Bottai4,A. Bruno6,F. Cafagna7,D. Campana1,P. Carlson10,M. Casolino11,12,G. Castellini13,C. De Donato11,14,C. De Santis11,14,N. De Simone11,V. Di Felice11,15,V. Formato8,16,A. M. Galper17,U. Giaccari4,a,A. V. Karelin17,S. V. Koldashov17,S. Koldobskiy17,S. Y. Krutkov9,A. N. Kvashnin5,A. Leonov17,V. Malakhov17,L. Marcelli11,14,M. Martucci14,18,A. G. Mayorov17,W. Menn19,M. Mergé11,14,V. V. Mikhailov17,E. Mocchiutti8,A. Monaco6,7,N. Mori3,4,R. Munini8,16,G. Osteria1,F. Palma11,14,M. Pearce10,P. Picozza11,14,M. Ricci18,S. B. Ricciarini4,13,R. Sarkar8,b,V. Scotti1,2,M. Simon19,R. Sparvoli11,14,P. Spillantini3,4,Y. I. Stozhkov5,A. Vacchi8,E. Vannuccini4,G. I. Vasilyev9,S. A. Voronov17,Y. T. Yurkin17,G. Zampa8,and N. Zampa8
Received: 18 May 2015 – Revised: 17 Jul 2015 – Accepted: 20 Aug 2015 – Published: 09 Sep 2015
Abstract. The PAMELA experiment has been collecting data since 2006; its results indicate a rise in the positron fraction with respect to the sum of electrons and positrons in the cosmic-ray (CR) spectrum above 10 GeV. This excess can be due to additional sources, as SNRs or pulsars, which can lead to an anisotropy in the local CR positron, detectable from current experiments. We report on the analysis on spatial distributions of positron events collected by PAMELA, taking into account also the geomagnetic field effects. No significant deviation from the isotropy has been observed.