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Hot spot effect in subatomic physics

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the vacuum 2) propagation of “heat” into the body of the target (projectile) wherefrom it is eventually also emitted through particle production. Particles produced in process 1) will have higher energies than those due to process 2), because in the latter process the excitation energy is in part degraded. This gives rise to an asymmetry with respect to the leading particle, which should be detectable in an experimental event by event analysis. This effect was confirmed by Jacques Goldberg in K− p→ K− p π+ π− reactions at 14 GEV/c. This experiment represents the first observation of local equilibrium in hadronic interactions, allowing in principle a quantitative determination of heat conductivity in hadronic matter along the lines of Ref.3. This observation came as a surprise, because, although the electron proton scattering experiments had shown beyond any doubt that the nucleon had a finite size, it was a-priori not clear whether this size was sufficiently big for the hot spot effect to be observable, i. e. whether heat conductivity in hadronic matters was sufficiently small. Experiment4 suggests that this is the case.
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reaction is quite short (of the order of 10–10 seconds) and the propagation of "heat", i.e. of the excitation, through the finite sized body of the system takes a finite time, which is determined by the thermal conductivity of the matter the system is made of. Indications of the transition between local and global equilibrium in strong interaction particle physics started to emerge in the 1960s and early 1970s. In high-energy strong interactions equilibrium is usually not complete. In these reactions, with the increase of laboratory energy one observes that the transverse momenta of produced particles have a tail, which deviates from the single exponential
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experimental studies of hot spots in nuclear matter became a subject of current interest and a series of special meetings was dedicated to the topic of local equilibrium in strong interactions. The phenomena of hot spots, heat conduction and preequilibrium play also an important part in high-energy heavy ion reactions and in the search for the phase transition to quark matter.
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had been made in nuclear reactions and were also attributed to pre-equilibrium effects. This interpretation suggested that the equilibrium is neither instantaneous, nor global, but rather local in space and time. By predicting a specific asymmetry in peripheral high-energy hadron reactions based on the hot spot effect
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measurements of protons and gamma rays. Subsequently on the theoretical side the link between hot spots and limiting fragmentation and transparency in high-energy heavy ion reactions was analyzed and “drifting hot spots” for central collisions were studied. With the advent of heavy ion accelerators
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had calculated the corresponding heat conductivity. The interest in this phenomenon was resurrected in the 1970s by the work of Weiner and Weström who established the link between the hot spot model and the pre-equilibrium approach used in low-energy heavy-ion reactions. Experimentally the hot spot
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which retains a large proportion of the incoming energy. By taking the notion of peripheral literally Ref.2 suggested that in this kind of reaction the surface of the colliding hadrons is locally excited giving rise to a hot spot, which is de-excited by two processes: 1) emission of particles into
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spectrum, characteristic for global equilibrium. The slope or the effective temperature of this transverse momentum tail increases with increasing energy. These large transverse momenta were interpreted as being due to particles, which "leak" out before equilibrium is reached. Similar observations
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Local equilibrium is the precursor of global equilibrium and the hot spot effect can be used to determine how fast, if at all, the transition from local to global equilibrium takes place. That this transition does not always happen follows from the fact that the duration of a strong interaction
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are statistical. The use of statistical methods assumes a large number of degrees of freedom. In macroscopic physics this number usually refers to the number of atoms or molecules, while in nuclear and particle physics it refers to the energy level density.
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proposed a direct test of this hypothesis as well as of the assumption that the heat conductivity in hadronic matter is relatively small. The theoretical analysis of the hot spot effect in terms of propagation of heat was performed in Ref.
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In high-energy hadron reactions one distinguishes peripheral reactions with low multiplicity and central collisions with high multiplicity. Peripheral reactions are also characterized by the existence of a
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Ho, H.; Albrecht, R.; DĂŒnnweber, W.; Graw, G.; Steadman, S. G.; Wurm, J. P.; Disdier, D.; Rauch, V.; Scheibling, F. (1977). "Pre-equilibrium alpha emission accompanying deep-inelastic O+Ni collisions".
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Galin, J.; Oeschler, H.; Song, S.; Borderie, B.; Rivet, M. F.; et al. (28 June 1982). "Evidence for a Limitation of the Linear Momentum Transfer in C-Induced Reactions between 30 and 84 MeV/u".
353:(1938). "Proceedings of the American Physical Society, Minutes of the New York Meeting February 25-26 1938. Abstract 3: Possible Deviations from the Evaporation Model of Nuclear Reactions". 719:
Trautmann, W.; Hansen, Ole; Tricoire, H.; Hering, W.; Ritzka, R.; Trombik, W. (22 October 1984). "Dynamics of Incomplete Fusion Reactions fromÎł-Ray Circular-Polarization Measurements".
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Westerberg, L.; Sarantites, D. G.; Hensley, D. C.; Dayras, R. A.; Halbert, M. L.; Barker, J. H. (1 July 1978). "Pre-equilibrium particle emission from fusion of C+Gd and Ne+Nd".
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Nomura, T.; Utsunomiya, H.; Motobayashi, T.; Inamura, T.; Yanokura, M. (13 March 1978). "Statistical Analysis of Preequilibriumα-Particle Spectra and Possible Local Heating".
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Sugitate, T.; Nomura, T.; Ishihara, M.; Gono, Y.; Utsunomiya, H.; Ieki, K.; Kohmoto, S. (1982). "Polarization of preequilibrium proton emission in the 93Nb + 14N reaction".
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In atomic nuclei, because of their larger dimensions as compared with nucleons, statistical and thermodynamical concepts have been used already in the 1930s.
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Gyulassy, Miklos; Rischke, Dirk H.; Zhang, Bin (1997). "Hot spots and turbulent initial conditions of quark-gluon plasmas in nuclear collisions".
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Beckmann, R; Raha, S; Stelte, N; Weiner, R M (1 February 1984). "Limiting Fragmentation and Transparency in High Energy Heavy Ion Collisions".
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Utsunomiya, H.; Nomura, T.; Inamura, T.; Sugitate, T.; Motobayashi, T. (1980). "Preequilibrium α-particle emission in heavy-ion reactions".
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Beckmann, R.; Raha, S.; Stelte, N.; Weiner, R.M. (1981). "Limiting fragmentation in high-energy heavy-ion reactions and preequilibrium".
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J. M. Miller, in Proc lnt. Conf. on nuclear physics, voL 2, ed. J. de Boer and H. J. Mang (North-Holland, Amsterdam, 1973) p. 398.
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model in nuclear reactions was confirmed in a series of investigations some of which of rather sophisticated nature including
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Fowler, G.N.; Raha, S.; Stelte, N.; Weiner, R.M. (1982). "Solitons in nucleus-nucleus collisions near the speed of sound".
920:“Correlations and Multiparticle Production” (LESI IV), Eds. M. PlĂŒmer, S. Raha and R. M. Weiner, World Scientific 1991. 893:“Local Equilibrium in Strong Interactions Physics” (LESIP I), Eds. D. K. Scott and R. M. Weiner, World Scientific 1985 40: 373: 1129: 127: 1018:
Raha, S.; Wehrberger, K.; Weiner, R.M. (1985). "Stability of density solitons formed in nuclear collisions".
911:“Hadronic Matter in Collision 1988” (LESIP III), Eds. P. Carruthers and J. Rafelski, World Scientific 1988 297:
Goldberg, Jacques (23 July 1979). "Observation of Preequilibrium Pion Evaporation from Excited Hadrons?".
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Hot spots are a manifestation of the finite size of the system: in subatomic physics this refers both to
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on nuclei and nucleons. For nuclei in particular finite size effects manifest themselves also in the
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Weiner, R.; Weström, M. (1977). "Diffusion of heat in nuclear matter and preequilibrium phenomena".
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had suggested that propagation of heat in nuclear matter could be studied in central collisions and
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Hadronic Matter in Collision” (LESIP II) Eds. P. Carruthers and D. Strottman, World Scientific 1986
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Weiner, R.; Weström, M. (16 June 1975). "Pre-equilibrium and Heat Conduction in Nuclear Matter".
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Raha, S.; Weiner, R. M. (7 February 1983). "Are Solitons Already Seen in Heavy-Ion Reactions?".
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Cf. e.g. Richard M. Weiner, Analogies in Physics and Life, World Scientific 2008, p. 123.
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physics are regions of high energy density or temperature in hadronic or nuclear matter.
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In this short abstract a forward-backward asymmetry in central collisions is considered.
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Weiner, Richard M. (18 March 1974). "Asymmetry in Peripheral Production Processes".
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Weiner, Richard M. (1 February 1976). "Propagation of "heat" in hadronic matter".
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Talk:Hot spot effect in subatomic physics § Largely incomprehensible
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Stelte, N.; Weström, M.; Weiner, R.M. (1982). "Drifting hot spots".
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in the medium is sufficiently small. The notions of equilibrium and
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Stelte, N.; Weiner, R. (1981). "Cumulative effect and hot spots".
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The formation of hot spots assumes the establishment of local
15: 384:(9–10). Springer Science and Business Media LLC: 573–604. 544:(3). Springer Science and Business Media LLC: 235–245. 98:, as well as to nucleons themselves, which are made of 1096:(26). American Physical Society (APS): 1787–1790. 727:(17). American Physical Society (APS): 1630–1633. 427:(24). American Physical Society (APS): 1523–1527. 339:. Vol. 19, no. 1. 1979. pp. 24–25. 270:(5). American Physical Society (APS): 1363–1375. 587:(11). American Physical Society (APS): 694–697. 235:(11). American Physical Society (APS): 630–633. 1061:(6). American Physical Society (APS): 407–408. 622:(2). American Physical Society (APS): 796–814. 305:(4). American Physical Society (APS): 250–252. 8: 943: 489:Blann, M (1975). "Preequilibrium Decay". 63:Learn how and when to remove this message 122:Statistical methods in subatomic physics 210: 43:. There is a discussion about this on 7: 505:10.1146/annurev.ns.25.120175.001011 130:, which in its turn occurs if the 14: 492:Annual Review of Nuclear Science 20: 797:(3). IOP Publishing: 197–201. 499:(1). Annual Reviews: 123–166. 1: 954:10.1016/s0375-9474(96)00416-2 867:(1–2). Elsevier BV: 190–210. 832:(4–5). Elsevier BV: 275–280. 333:"Hot spots discussed at Bonn" 1032:10.1016/0375-9474(85)90274-x 997:10.1016/0370-2693(82)90371-9 873:10.1016/0375-9474(82)90313-x 838:10.1016/0370-2693(81)90223-9 768:10.1016/0370-2693(81)91194-1 698:10.1016/0375-9474(82)90422-5 663:10.1016/0375-9474(80)90144-x 468:10.1016/0375-9474(77)90408-0 1102:10.1103/physrevlett.48.1787 1026:(3). Elsevier BV: 427–440. 991:(4). Elsevier BV: 286–290. 762:(6). Elsevier BV: 411–416. 733:10.1103/physrevlett.53.1630 692:(2). Elsevier BV: 402–420. 657:(1). Elsevier BV: 127–143. 462:(2). 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Index

confusing or unclear
clarify the article
Talk:Hot spot effect in subatomic physics § Largely incomprehensible
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subatomic
atomic nuclei
nucleons
quarks
gluons
electrons
isomeric shift
isotopic shift
equilibrium
thermal conductivity
heat
Boltzmann
Richard M. Weiner
Hans Bethe
Sin-Itiro Tomonaga
polarization
solitons
doi
10.1103/physrevlett.32.630
ISSN
0031-9007
doi
10.1103/physrevd.13.1363
ISSN
0556-2821
doi

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