1. A.A.Petrukhin National Research Nuclear University MEPhI, Moscow, Russia New ideas about cosmic ray investigations above the knee Contents: 1.Introduction. 2.Cosmophysical approach. 3.Nuclear-physical approach. 4.Explanation of unusual events in CR. 5.Role of nuclei-nuclei interactions. 6.How to check new approach? 7.Conclusion.

2. Introduction Introduction 100 years of cosmic rays and 50 years of the knee. In the 1 st paper (Kulikov & Khristiansen, 1958) both possible interpretations of the knee origin (cosmophysical and nuclear-physical) were discussed. Both these interpretations are connected with problem of cosmic ray origin (galactic or extragalactic). But the knee itself is the result of interpretation of measured EAS parameters.

3. Existing approach to EAS analysis

4. Basic ideas of the existing approach Basic ideas of the existing approach EAS energy is equal to the energy of primary particle. All changes of EAS characteristics in dependence on energy are results of energy spectrum or/and composition changes only. Primary cosmic rays have galactic origin. Their acceleration and keeping in Galaxy are determined by their charge Z or/and mass A. And the following results were obtained:

5. Results of energy spectrum “measurements” Results of energy spectrum “measurements” Really, in the best case, EAS energy can be evaluated.

6. Results of energy spectrum interpretation

7. Results of composition “investigations” Results of composition “investigations” Really, N  / N e – ratio and X max are measured.

8. Results of X max measurements

9. Some remarks In spite of interesting ideas and numerous calculations of not one generation of scientists, a satisfactory description of changes of the energy spectrum and mass composition above the knee in frame of the cosmophysical approach has not been found. Experimental results of N  /N e and X max measurements contradict this approach. The problem of UHE cosmic ray origin is not clear. If the sources of such particles exist in other galaxies, why they do not exist in our Galaxy?

10. Basic ideas of nuclear-physical approach Naturally, in this case primary cosmic ray spectrum and composition are not changed and their sources must be the same in the whole Universe. EAS energy is not equal to primary particle energy: E EAS = E 2 < E 1 The knee is the result of inclusion of new processes of interaction or/and production of new particles, states of matter, etc.

11. Two main difficulties of nuclear physical approach Large cross section of new processes which is required to change the cosmic ray energy spectrum. Many physicists speak about new physics (new particles, etc.) in TeV energy region (in the center of mass system which corresponds to PeV energy region in cosmic ray experiments) but with low cross sections: nb or pb. Where the difference between primary particle energy and EAS energy disappears? In favor of possibility of appearance of new processes (particles, states of matter, etc.) evident numerous unusual events which were detected in various experiments at energies above the knee.

12. List of unusual events List of unusual events  In hadron experiments:  In EAS investigations (in this approach we can consider): Important: Unusual events appear at PeV energies of primary particles. halos, alignment, penetrating cascades, Centauros (Pamir-Chacaltaya);  long-flying component, Anti-Centauros (Tien-Shan).  In muon experiments: excess of VHE (~ 100 TeV) single (MSU) and multiple (LVD) muons;  observation of VHE muons (Japan, NUSEX), the probability to detect which is very small. change of EAS energy spectrum in the atmosphere, which now is interpreted as a change of primary energy spectrum.    changes of behavior of N  (N e ) and X max (N e ) dependences, which now are explained as the heaving of composition. 

13. Halo and alignment Halo and alignment

14. Penetrating cascades Penetrating cascades

15. Muon flux excess Muon flux excess

16. Excess of muon bundles Excess of muon bundles

17. The knee as a result of new interaction The knee as a result of new interaction In this case a difference between primary and EAS energies, so-called missing energy, appears.

18. What do we need to explain all unusual data? What do we need to explain all unusual data? Model of hadron interactions which gives: 1.Threshold behaviour (unusual events appear at several PeV only). 2. Large cross section (to change EAS spectrum slope). 3. Large yield of leptons (excess of VHE muons, missing energy and penetrating cascades). 4. Large orbital (or rotational) momentum (alignment). 5. More quick development of EAS (for increasing the N  / N e ratio and decreasing X max elongation rate).

19. Possible variants Inclusion of new super-strong interaction. Appearance of new massive particles (supersymmetric, Higgs-bosons, relatively long-lived resonances, etc.) Production of blobs of quark-gluon plasma (QGP) (better to speak about quark-gluon matter (QGM), since usual plasma is a gas but quark-gluon is a liquid). We considered the last model since it allows demonstrably explain the inclusion of new interaction.

20. Quark-gluon matter Quark-gluon matter 1. Production of QGM provides main conditions: - threshold behavior, since for that large temperature (energy) is required; - large cross section, since the transition from quark-quark interaction to some collective interaction of many quarks occurs: 2. But for explanation of other observed phenomena a large value of orbital angular momentum is required. where R, R 1 and R 2 are sizes of quark-gluon blobs

21. Orbital angular momentum in non-central ion-ion collisions Zuo-Tang Liang and Xin-Nian Wang, PRL 94, 102301 (2005); 96, 039901 (2006)

22. Centrifugal barrier 1.As was shown by Zuo-Tang Liang and Xin-Nian Vang, in non-central collisions a globally polarized QGP with large orbital angular momentum which increases with energy appears. 2.In this case, such state of quark-gluon matter can be considered as a usual resonance with a large centrifugal barrier. 3.Centrifugal barrier will be large for light quarks but less for top-quarks or other heavy particles.

23. Centrifugal barrier for different masses

24. How EAS development is changed in frame of a new model? 1.Simultaneous interactions of many quarks change the energy in the center of mass system drastically: 2.Produced -quarks take away energy GeV, and taking into account fly-out energy,  t > 4 m t  700 GeV (in the center of mass system). 3.Decays of top-quarks W W –bosons decay into leptons ( ~30% ) and hadrons (~70% ); b  c  s  u b  c  s  u with production of muons and neutrinos. where m c  nm N. At threshold energy, n ~ 4 (  - particle)

25. How the energy spectrum is changed? 1.One part of t-quark energy gives the missing energy ( e, , ,  ), and another part changes EAS development, especially its beginning, parameters of which are not measured. 2.As a result, measured EAS energy E 2 will not be equal to primary particle energy E 1 and the measured spectrum will be differed from the primary spectrum. 3.Transition of particles from energy E 1 to energy E 2 gives a bump in the energy spectrum near E 2.

26. Change of primary energy spectrum

27. How measured composition is changed in frame of the new approach Since for QGM production not only high temperature (energy) but also high density is required, threshold energy for production of new state of matter for heavy nuclei will be less than for light nuclei and protons. Therefore the heavy nuclei (f.e., iron) spectrum is changed earlier than light nuclei and proton spectra!!! To compare the changes of spectra of different nuclei, very simple model was used.

28. Relation between primary energy E 1 and measured energy E 2 n = 4  t = 700 GeV

29. Primary spectra of various nuclei

30. Measured spectra for some nuclei and spectrum of all particles

31. Influence of energy straggling

32. Comparison with experimental data (without straggling)

33. Comparison with experimental data (with 10% straggling)

34. Discussion of results 1.Energy spectrum obtained in frame of the simplest model surprisingly well describes experimental data. 2.Changes of composition are explained: –a sharp increase of average mass at the expense of detection of EAS from heavy nuclei, –after that slow transition to proton composition. 3.Results of composition changes obtained by means of N  measurements are explained, too. Number of muons is increased as result of not muon production in nuclei interaction but through decays of massive particles.

35. EAS simulations in frame of the new approach CORSIKA (version 6.960) was used. To introduce -quarks, PYTHIA (version 6.4.22) was used. Unfortunately, PYTHIA describes pp-interactions only, but in spite of this the obtained results are impressive. The following results were obtained: - changes of various particle spectra in EAS after introduction of t-quark; - changes of inclusive muon energy spectrum; - comparison of cascades from nuclei without t-quarks and cascades from protons with t-quarks.

36. Various particle spectra without t-quarks

37. Various particle spectra with t-quarks

38. Inclusive muon energy spectrum

39. Cascade curves for various nuclei (without t-quarks)

40. Cascade curves for protons (with t-quarks)

41. The ankle problem

42. Explanation of the ankle appearance On the face of it, the considered approach does not explain the behavior of the energy spectrum above the ankle, but this is not so. With increasing of primary particle energy the excitation level can exceed the centrifugal barrier, and the blob of QGM will decay into light quarks.

43. The kneeThe ankle Illustration of the ankle appearance 10 17 eV10 18 eV In this case, there will be no missing energy and the measured spectrum begins to return to the initial form (  = 2.7).

44. How to check the new approach? There are several possibilities to check new approach as in LHC experiments so in cosmic ray investigations. Of course, the most convincing results in LHC experiments can be obtained, since QGM with described characteristics (excess of t-quarks, excess of VHE muons, sharp increasing of missing energy, etc.) doubtless will be observed. However these results unlikely can be obtained in pp-interactions even at full energy 14 TeV, which correspond 10 17 eV in cosmic ray experiments (for pp-interaction), since for that collisions of sufficiently heavy nuclei are required.

45. How to check the new approach in cosmic ray experiments? One possibility is direct measurements of various nuclei spectra in space. Changes in spectra must begin from heavy nuclei. Two other possibilities are connected with VHE muon detection: - measurements of muon energy spectrum above 100 TeV; - measurements of energy deposit of EAS muon component below and above the knee. For that, existing muon and neutrino detectors can be used: BUST, NEVOD-DECOR, Baikal, ANTARES, IceCube etc.

46. Prediction for CR nuclei spectra measurements

47. Results of VHE muon measurements

48. Preliminary results of muon energy spectrum investigations in Baksan Underground Scintillation Telescope (BUST) http://arxiv.org/pdf/0911.1692

49. Expected results of muon energy deposit measurements Expected results of muon energy deposit measurements E1E1

50. Existing approach to EAS analysis

51. New approach to EAS analysis

52. Conclusion Considered approach allows solve practically all problems of comic ray investigations above the knee. If this approach is correct, it will be an excellent present to 100 year anniversary of cosmic ray discovery! And it will provide a good job for next generations of cosmic ray physicists during the second century of cosmic ray investigations!

53. Thank you!

55. The model of cosmic ray generation in plasma pinches B.A.Trubnikov, V.P.Vlasov, S.K.Zhdanov Kurchatov Institute, Moscow (Preprint № 4828/6 IAE, M., 1989; JETP Lett., 1989, v.49, p.581.) In cosmic plasma (of any origin) electrical discharges – "cosmic lightnings" can occur, at which cylindrical pinches are formed. Two basic instabilities of plasma pinches are known: snaky and neck. In the last case plasma jets are squeezed out of pinch neck. These jets are the accelerated particle beams. Snaky Neck

56. It is shown that energy distribution of particles in jets has the following form: which does not depend on pinch sizes, currents in pinches and other parameters. These parameters determine a proportionality coefficient only. Accelerated particle energy has no limitation since density in plasma pinch   when its radius  0. Therefore the contribution of various sources of cosmic plasma (stars, Supernova, Galaxy, black holes, etc.) can be summed and general spectrum in whole Universe is formed. Model explains the absence of point sources of cosmic rays since plasma pinches, f.e. near Supernovae, can be oriented in any direction. Energy spectrum of accelerated particles