Cosmic Rays  

In General > s.a. astrophysics; cosmic-ray sources and propagation.
* Idea: Particles of astrophysical (including the Sun and galactic sources) and cosmological origin arriving on Earth.
* History: 1912, First seen by Viktor Hess in a 5-km-high balloon flight; Named by Millikan; 1938, P Auger saw coincidences over distances > 1 km; Important for hep up to the 1950s, then accelerator data dominated; 1960s, E > 1020 eV event detected by J Linsley; 1966, GZK prediction of 5 × 1019 eV cutoff; 1980s, Renaissance in the form of search for high-energy photons from pointlike astronomical sources (apparently up to 103 TeV!), in the hope of getting undisturbed information on the source; 2010s, They are providing a window on extragalactic astrophysics; 2013, There is conclusive evidence that at least some of the cosmic rays come from supernova remnants.
@ I: Ramaty et al PT(98)apr, ThSc(99)nov; Friedlander 00.
@ Intros, reviews: Ginzburg SPU(96); Baring AIP(00)ap/99; Dar et al ap/99/PRL [origin]; Ellis NCC(01)ap/00-in [and HEP]; Biermann & Sigl LNP(01)ap/02 [intro]; Moskalenko ap/04-conf [propagation]; Hörandel IJMPA(05)ap-conf [measurements]; Parizot ap/05-proc [whole spectrum]; Ferrari & Szuszkiewicz ap/06; Dar in(05)ap/06 [origin]; Hillas ap/06-conf; De Rújula a0711-ln; Sommers & Westerhoff NJP(09)-a0802; Gelmini JPCS(09)-a0903; issue NPPS(09)190; Gaisser a1010-conf; Bietenholz a1305 [and high-energy cutoff]; Blandford et al NPPS(14)-a1409 [origin]; D'Urso a1411-proc [observation]; Gaisser et al 16 [and particle physics].
@ General theory: Dar & De Rújula PRP(08) [single theory of non-solar cosmic rays]; González-Mestres NPPS(11)-a1011 [and fundamental physics]; Yalcin & Beck a1705 [generalized statistical mechanics]; Lipari a1707 [spectral features].
@ History: Pacini LeRa(1911)-a1101; Fields & Prodanović ApJ(05)ap/04 [from 6Li]; De Angelis et al a1002 [Domenico Pacini]; Muraki NPPS(11)-a1012; Carlson & De Angelis EPJH(10)-a1012 [and internationalism in science]; De Angelis RNC-a1103 [Domenico Pacini]; issue NPPS(11)212; Bonolis a1110, a1211-conf [Bruno Rossi]; Carlson PT(12)feb; Kampert & Watson EPJH(12)-a1207 [extensive air showers]; De Angelis APP(14)-a1208-conf [before 1912]; Bonolis a1304 [Bruno Rossi and the 1930s].

Properties and Effects on Earth > s.a. statistics [non-extensive]; ultra-high-energy cosmic rays.
* Rates on Earth: At the surface we get about 1 muon/cm2/min; For primaries, the energy ranges from 109 to 1019 eV, with a spectrum that drops sharply with E; We get about 1 event/m2/s at 1011 eV, 1 event/m2/yr at 1016 eV (the "knee"), and 1 event/m2/cy at 1019 eV (the "ankle").
* Composition: At a given energy, the ratio of protons to antiprotons is more than 10,000 to 1 (numbers are consistent with the levels of antiprotons expected from collisions between high-energy protons in cosmic rays and the nuclei of hydrogen and helium atoms in the interstellar medium), and electrons 100 to 1000 times less abundant than protons.
* Positron and electron excess: 2009, Is it due to the annihilation of dark matter particles, or can it be explained by natural astrophysical processes? The former explanation would probably imply an excess of antiprotons with respect to secondary production in the interstellar medium, which was not observed; 2010, New PAMELA results are still consistent with all antiprotons coming from secondary production, but there is sufficient uncertainty to allow for dark matter annihilation; 2017, Positron excess may be due to collisions of white dwarf stars; > s.a. dark-matter detection.
* Anomalous cosmic rays: Accelerated at the termination shock, where the solar wind meets interstellar space.
@ Composition: Kampert ap/02-conf [chemistry]; Adriani et al PRL(09) + Swordy Phy(09) [antiprotons]; Abraham et Pierre Auger a0906-conf; Kampert & Unger APP(12)-a1201; Tamburro et IceCube a1307-proc; > s.a. ultra-high energy cosmic rays.
@ Positron and electron excess: Blasi PRL(09)-a0903; Bergström et al PRL(09)-a0905 [dark-matter interpretation]; Pato et al PRD(09)-a0905; Schubnell a0905-proc; Grasso et al APP(09)-a0905 [possible interpretations]; Cowsik & Burch a0906-in [nested-leaky-box model]; Sau et al HJ(08)-a0906; Biermann et al PRL(09) [electrons and positrons from supernovae]; Shaviv PRL(09) [inhomogeneity of sources]; Lavalle AIP(10)-a0911 [assessment of dark-matter annihilation proposal]; Brun et al a1001-proc [rev]; Adriani et al PRL(10) [p-bar flux], PRL(11) [electron flux], PRL(13) [positron spectrum]; Ackermann et al PRL(12); news pw(13)aug; news pw(13)nov [does it really exist?]; news pw(14)apr [can pulsars explain it?]; Boudaud et al A&A(15)-a1410; Laletin a1705-proc [not explained by dark matter]; news sa(17)may [positrons from collisions of white dwarf stars].
@ Effects on Earth: Dar et al PRL(98) [life extinctions?]; Shaviv PRL(02) [climate and spiral-arm crossings]; Harrison & Stephenson PRA(06) [on clouds]; Atri et al JCAP(10)-a0804 [atmospheric chemistry]; news pw(11)may [clouds]; Atri & Melott APP(14)-a1211 [and terrestrial life]; Sloan & Wolfendale NA(13)-a1303 [climate change]; news pw(13)sep [clouds]; Dreiling & Gay PRL(14) [Vester-Ulbrict hypothesis]; > s.a. earth [atmospheric electricity, lightning].
> Related topics: see astrophysical neutrinos; phenomenology of magnetism [particle acceleration].

Experiments and Other Phenomena > s.a. astronomy; astrophysical neutrinos; PAMELA; Pierre Auger Observatory.
* Projects: 2004, The Pierre Auger project starts operating with a portion of its 1600 detectors, an array of water detectors to measure showers with E > 1019 eV; 2007, Pierre Auger project scheduled for completion; Extreme Universe Space Observatory in 2008?
@ Air showers: Anchordoqui et al AP(04)hp; Werner et al ap/04-conf; Fargion ap/05-conf [horizontal showers]; Dova AP-ap/05-conf; Drescher & Farrar APP(05)ap [AGASA]; Ahn & Cavaglià PRD(06) [black hole showers, simulations].
@ Balloon-borne: Cherry JPCS(06)ap/05 [towards higher E]; Hoover et al PRL(10)-a1005 [ultra-high-energy cosmic rays, ANITA].
@ Other projects: Pacini NC(12), translation De Angelis a1002 [early work]; Enqvist et al JPCS(06)ap/05 [EMMA]; Casolino et Pamela JPSJ(08)-a0810-proc, a0904-conf [Pamela satellite experiment]; Baldini a1407-ln [space-based, rev].
@ Other topics: Abbasi et Fly's Eye PRL(04) [observed flux]; Parker SA(03)mar [danger for space travelers]; Abdo et Milagro PRL(08) + Kampert Phy(08) [localized excess fluxes at 10 TeV]; blog motheyes(11)sep [cosmic rays and global warming?]; Rimmer et al ApJL(14)-a1405 [Jupiter as a giant detector]; Privitera & Motloch ApJL(14)-a1405 [Jupiter not viable]; Mocchiutti NPPS(14)-a1407 [precision measurements]; Scherer et al APP(16)-a1607 [comic ray (sic)]; Meehan et al a1708-conf [DECO, the cell-phone application for cosmic ray detecton].

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