APS » Phys. Rev. D » Volume 76 » Issue 5

P. Adamson,^1,2 C. Andreopoulos,³ K. E. Arms,⁴ R. Armstrong,⁵ D. J. Auty,⁶ S. Avvakumov,⁷ D. S. Ayres,⁸ B. Baller,¹ B. Barish,⁹ P. D. Barnes, Jr.,¹⁰ G. Barr,¹¹ W. L. Barrett,¹² E. Beall,^4,8 B. R. Becker,⁴ A. Belias,³ T. Bergfeld,¹³ R. H. Bernstein,¹ D. Bhattacharya,¹⁴ M. Bishai,¹⁵ A. Blake,¹⁶ B. Bock,¹⁷ G. J. Bock,¹ J. Boehm,¹⁸ D. J. Boehnlein,¹ D. Bogert,¹ P. M. Border,⁴ C. Bower,⁵ E. Buckley-Geer,¹ C. Bungau,⁶ A. Cabrera,¹¹ J. D. Chapman,¹⁶ D. Cherdack,¹⁹ S. Childress,¹ B. C. Choudhary,¹ J. H. Cobb,¹¹ A. J. Culling,¹⁶ J. K. de Jong,²⁰ A. De Santo,¹¹ M. Dierckxsens,¹⁵ M. V. Diwan,¹⁵ M. Dorman,^2,3 D. Drakoulakos,²¹ T. Durkin,³ A. R. Erwin,²² C. O. Escobar,²³ J. J. Evans,¹¹ E. Falk Harris,⁶ G. J. Feldman,¹⁸ T. H. Fields,⁸ R. Ford,¹ M. V. Frohne,²⁴ H. R. Gallagher,¹⁹ G. A. Giurgiu,⁸ A. Godley,¹³ J. Gogos,⁴ M. C. Goodman,⁸ P. Gouffon,²⁵ R. Gran,¹⁷ E. W. Grashorn,^4,17 N. Grossman,¹ K. Grzelak,¹¹ A. Habig,¹⁷ D. Harris,¹ P. G. Harris,⁶ J. Hartnell,³ E. P. Hartouni,¹⁰ R. Hatcher,¹ K. Heller,⁴ A. Holin,² C. Howcroft,⁹ J. Hylen,¹ D. Indurthy,²⁶ G. M. Irwin,⁷ M. Ishitsuka,⁵ D. E. Jaffe,¹⁵ C. James,¹ L. Jenner,² D. Jensen,¹ T. Joffe-Minor,⁸ T. Kafka,¹⁹ H. J. Kang,⁷ S. M. S. Kasahara,⁴ M. S. Kim,¹⁴ G. Koizumi,¹ S. Kopp,²⁶ M. Kordosky,² D. J. Koskinen,² S. K. Kotelnikov,²⁷ A. Kreymer,¹ S. Kumaratunga,⁴ K. Lang,²⁶ A. Lebedev,¹⁸ R. Lee,¹⁸ J. Ling,¹³ J. Liu,²⁶ P. J. Litchfield,⁴ R. P. Litchfield,¹¹ P. Lucas,¹ W. A. Mann,¹⁹ A. Marchionni,¹ A. D. Marino,¹ M. L. Marshak,⁴ J. S. Marshall,¹⁶ N. Mayer,¹⁷ A. M. McGowan,^4,8 J. R. Meier,⁴ G. I. Merzon,²⁷ M. D. Messier,⁵ D. G. Michael,⁹ R. H. Milburn,¹⁹ J. L. Miller,²⁸ W. H. Miller,⁴ S. R. Mishra,¹³ A. Mislivec,¹⁷ P. S. Miyagawa,¹¹ C. D. Moore,¹ J. Morfín,¹ L. Mualem,⁴ S. Mufson,⁵ S. Murgia,⁷ J. Musser,⁵ D. Naples,¹⁴ J. K. Nelson,²⁹ H. B. Newman,⁹ R. J. Nichol,² T. C. Nicholls,³ J. P. Ochoa-Ricoux,⁹ W. P. Oliver,¹⁹ T. Osiecki,²⁶ R. Ospanov,²⁶ J. Paley,⁵ V. Paolone,¹⁴ A. Para,¹ T. Patzak,³⁰ Ž. Pavlović,²⁶ G. F. Pearce,³ C. W. Peck,⁹ E. A. Peterson,⁴ D. A. Petyt,⁴ H. Ping,²² R. Piteira,³⁰ R. Pittam,¹¹ R. K. Plunkett,¹ D. Rahman,⁴ R. A. Rameika,¹ T. M. Raufer,¹¹ B. Rebel,¹ J. Reichenbacher,⁸ D. E. Reyna,⁸ C. Rosenfeld,¹³ H. A. Rubin,²⁰ K. Ruddick,⁴ V. A. Ryabov,²⁷ R. Saakyan,² M. C. Sanchez,¹⁸ N. Saoulidou,¹ J. Schneps,¹⁹ P. Schreiner,²⁴ V. K. Semenov,³¹ S.-M. Seun,¹⁸ P. Shanahan,¹ W. Smart,¹ V. Smirnitsky,³² C. Smith,^2,6 A. Sousa,^11,19 B. Speakman,⁴ P. Stamoulis,²¹ P. A. Symes,⁶ N. Tagg,^11,19 R. L. Talaga,⁸ E. Tetteh-Lartey,³³ J. Thomas,² J. Thompson,¹⁴ M. A. Thomson,¹⁶ J. L. Thron,⁸ G. Tinti,¹¹ I. Trostin,³² V. A. Tsarev,²⁷ G. Tzanakos,²¹ J. Urheim,⁵ P. Vahle,² C. Velissaris,²² V. Verebryusov,³² B. Viren,¹⁵ C. P. Ward,¹⁶ D. R. Ward,¹⁶ M. Watabe,³³ A. Weber,^3,11 R. C. Webb,³³ A. Wehmann,¹ N. West,¹¹ C. White,²⁰ S. G. Wojcicki,⁷ D. M. Wright,¹⁰ Q. K. Wu,¹³ T. Yang,⁷ F. X. Yumiceva,²⁹ H. Zheng,⁹ M. Zois,²¹ and R. Zwaska¹

(MINOS Collaboration)

¹Fermi National Accelerator Laboratory, Batavia, Illinois 60510, USA
²Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
³Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX, UK
⁴University of Minnesota, Minneapolis, Minnesota 55455, USA
⁵Departments of Physics and Astronomy, Indiana University, Bloomington, Indiana 47405, USA
⁶Department of Physics and Astronomy, University of Sussex, Falmer, Brighton BN1 9QH, UK
⁷Department of Physics, Stanford University, Stanford, California 94305, USA
⁸Argonne National Laboratory, Argonne, Illinois 60439, USA
⁹Lauritsen Lab, California Institute of Technology, Pasadena, California 91125, USA
¹⁰Lawrence Livermore National Laboratory, Livermore, California 94550, USA
¹¹Subdepartment of Particle Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
¹²Physics Department, Western Washington University, Bellingham, Washington 98225, USA
¹³Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA
¹⁴Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
¹⁵Brookhaven National Laboratory, Upton, New York 11973, USA
¹⁶Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK
¹⁷Department of Physics, University of Minnesota–Duluth, Duluth, Minnesota 55812, USA
¹⁸Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
¹⁹Physics Department, Tufts University, Medford, Massachusetts 02155, USA
²⁰Physics Division, Illinois Institute of Technology, Chicago, Illinois 60616, USA
²¹Department of Physics, University of Athens, GR-15771 Athens, Greece
²²Physics Department, University of Wisconsin, Madison, Wisconsin 53706, USA
²³Universidade Estadual de Campinas, IF-UNICAMP, CP 6165, 13083-970, Campinas, São Paulo, Brazil
²⁴Physics Department, Benedictine University, Lisle, Illinois 60532, USA
²⁵Instituto de Física, Universidade de São Paulo, CP 66318, 05315-970, São Paulo, São Paulo, Brazil
²⁶Department of Physics, University of Texas, 1 University Station, Austin, Texas 78712, USA
²⁷Nuclear Physics Department, Lebedev Physical Institute, Leninsky Prospect 53, 117924 Moscow, Russia
²⁸Physics Department, James Madison University, Harrisonburg, Virginia 22807, USA
²⁹Department of Physics, College of William and Mary, Williamsburg, Virginia 23187, USA
³⁰APC–Collège de France, 11 Place Marcelin Berthelot, F-75231 Paris Cedex 05, France
³¹Institute for High Energy Physics, Protvino, Moscow Region RU-140284, Russia
³²High Energy Experiment Physics Department, Institute of Theoretical and Experimental Physics, B. Cheremushkinskaya, 25, 117218 Moscow, Russia
³³Physics Department, Texas A&M University, College Station, Texas 77843, USA

The 5.4 kton MINOS far detector has been taking charge-separated cosmic ray muon data since the beginning of August, 2003 at a depth of 2070 m.w.e. in the Soudan Underground Laboratory, Minnesota, USA. The data with both forward and reversed magnetic field running configurations were combined to minimize systematic errors in the determination of the underground muon charge ratio. When averaged, two independent analyses find the charge ratio underground to be N_µ⁺/N_µ^-=1.374±0.004(stat)_-0.010^+0.012(sys). Using the map of the Soudan rock overburden, the muon momenta as measured underground were projected to the corresponding values at the surface in the energy range 1–7 TeV. Within this range of energies at the surface, the MINOS data are consistent with the charge ratio being energy independent at the 2 standard deviation level. When the MINOS results are compared with measurements at lower energies, a clear rise in the charge ratio in the energy range 0.3–1.0 TeV is apparent. A qualitative model shows that the rise is consistent with an increasing contribution of kaon decays to the muon charge ratio.

©2007 The American Physical Society

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