Nano-structures, Superfluids and superconductors

I do not know your background but naively speaking if I look from HEP side, the answer to this question is "many".  As a start  experimental HEP uses particle detector where huge amount of radiation and hence heat exposure is highly possible. Not to mention "beam dumps" where we use to stop high energy beams when we are done with them or in case of an emergency to abort.

Moreover, to be able to do particles physics experiments you need to get the relativistic particles from somewhere. And they are particle accelerators where have an entire spectrum from radio-frequency engineering to beam diagnostics where we highly rely on mechanical engineering. 

From the other point of view, you might have a look at concepts as RF breakdown, multipacting, phenomena observed in the presence of high energy particles or high fields. They might be interesting to look at from an mechanical engineer's eyes. 

Yes, se my articles: American Journal of Astronomy and Astrophysics

2014; 2(2): 1-7. And other papres in this special issue

Published online October 30, 2014 (http://www.sciencepublishinggroup.com/j/ajaa)

doi: 10.11648/j.ajaa.s.20140202.11

Global anisotropy and theory of byuon

Yuriy Alexeevich Baurov1, 2

1Closed Joint Stock Company Research Institute of Cosmic Physics, 141070, Moscow Region, Pionerskaya, 4, Korolyov, Russia

2Hotwater Srl, , Via Gioberti, 15, I-56024 San Miniato (PI), Italy

Email address:

baurov@mail.

In addition design of 'magnets' of various shapes for high energy accelerators.Very very long arms of Michelson-Morley type experimental set up to study and dtect gravitational waves as in the L shaped detector used by LIGO expt. LIGO L1 ans LIGO H1.

Avikshit,   You asked:  “Can there be an area that belongs to HEP but has implications in Mechanical Engineering?”   “Hydrodynamics” and “Geometric Scaling” are two areas of study that are part of both HEP and Mech. Eng.  Both areas of study are important in the analysis of data at the RHIC and LHC,  and they both give surprising and puzzling results in the interpretation of the data at these facilities.  For example,  here are 3 issues in HEP that were found using these theories.

Ref. 1)  In a recent article in “World Scientific” called “Introduction to Hydrodynamics” by Sangyong Jeon and Ulrich Heinz,  the authors deliver a general and pedagogic view of the relativistic hydrodynamics currently used in the study of ultra-relativistic heavy ion collisions.  Dynamics of collective motion (hydrodynamics) is an integral part of the theoretical modeling of such events.  In the theory of hydrodynamics,  strong elliptic transverse flow of scattered particles upon collision of heavy ions (such as Au+Au) is predicted,  and is consistent with experimental results at the RHIC and LHC. 

ISSUE:   However,  ‘elliptic flow’ is not predicted in the theory when the colliding particles are small,  although such flow (or jet flow) does occur in such experiments.  Regarding this,  the authors’ comment is in italics:  “More recently,  the systems created in the highest multiplicity proton-proton collisions and proton-nucleus collisions were also seen to exhibit strong collective behavior.  This is deeply puzzling, as the size of the system ought to be too small to behave collectively. It is hoped that more thorough investigation of the possible origin of the collectivity in such small systems can illuminate the inner workings of the QGP formation greatly.”   A link to the article is given here. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwj36JObpYLMAhVMRiYKHREsBwwQFggdMAA&url=http%3A%2F%2Farxiv.org%2Fpdf%2F1503.03931&usg=AFQjCNHsY6a-9HxTY-NvVJTf62QGtAEEoA

Ref. 2)  In another article in “Physical Review Letters”,  called “Observation of Direct-Photon Collective Flow in Au+Au Collisions at √sNN = 200  GeV”,  by A. Adare et al. (PHENIX Collaboration),  the authors examine the second Fourier component v2 of the azimuthal anisotropy [transverse elliptical flow] with respect to the reaction plane measured for direct-photons at mid-rapidity and transverse momentum (pT ) of 1–13 GeV/c. 

ISSUE:   For thermal photons (pT < 4 GeV/c),  the authors noted a positive direct-photon v2 is observed and is comparable in magnitude to the pion v2 and consistent with early thermalization times and low viscosity,  but its magnitude is much larger than current theories predict.  A link to the article is given here. http://arxiv.org/pdf/1105.4126.pdf

Ref. 3)  In a recent article in ELSEVIER’S “Physics Letters B”,  called “Geometrical scaling of direct-photon production in hadron collisions from RHIC to the LHC”  by Christian Klein-Böesing and Larry McLerran,  the authors show that geometric scaling provides a good description of the energy dependence of photon production in heavy ion + ion collisions,  including p + p  and  deuteron + Au scattering.  Geometrical scaling,  which is the scale invariance of transverse expansion of particles,  is only dependent on the saturation momentum of parent particles in the longitudinal interaction (collision).  In hydrodynamic expansion,  this can only occur in the initial stage of such interaction.

ISSUE:   The authors summarize their concern in their statement following in italics.  “Thus, our observation indicates that direct-photon production occurs mainly before the scale breaking effects of particle masses and system-size becomes important.  The former would be true if the system produces photons at an energy scale large compared to meson masses,  which might be possible.  The latter is more difficult, since flow measurements for photons demonstrate that they do have an azimuthal anisotropy [elliptic flow] with respect to the event reaction plane.  This is conventionally associated with transverse expansion and it requires that the photons be produced at times where the size of the system actually is important, [i.e., emitted incidentally after the collision from quark and gluon plasma (QGP) that arises from such collision].”   A link to the article is here.  http://www.sciencedirect.com/science/article/pii/S0370269314003736

EXAMINATION:  In the references above,  we notice that photon production likely occurs immediately upon collision of parent particles based on geometric scaling,  not from the QGP,  per Ref. 3;  however, there is a discrepancy because one would expect the photons to be emitted from the QGP since there is transverse elliptic flow of the medium. 

Nevertheless, on the other hand,  the scattered photons,  irrespective of any medium such as QGP,  may undergo transverse elliptic flow themselves if there is a sufficient quantity of them. This is consistent with bulk dynamics of collective motion (hydrodynamics) as shown to be necessary for elliptic flow in Ref. 1;  further, this would alleviate the concern in Ref. 1 that strong collective behavior is not possible when the colliding parent particles are small.  For example in experiments,  the scattered photons are exhibiting  such collective behavior,  instead of scattered quarks and gluons,  which are not of sufficient quantity.

This concept also addresses the issue presented in Ref. 2.  For example,  if photons are scattered from the collision,  not incidentally from the QGP,  then the transverse elliptic flow is given by the photons,  not the QGP.  Thus,  the quantity of such photons is significantly greater than the expectation amount of incidental photons from the QGP.  This, in turn, would yield a greater magnitude of the second Fourier component v2 of the azimuthal anisotropy due to a stronger collective motion of the photons.

In current theory,  high-energy particle collisions lead to the production of QGP,  then hadronization of the QGP occurs giving mostly unstable hadrons,  then decay of such hadrons occurs,  and from this,  successive re-hadronization to other particles and/or emission of photons occur.  However, the results of high-energy experiments and theories alluded to in the references above may point to different dynamics.  For example,  the dynamic structures of hadrons may only consist of photon formations.  Such photons are scattered upon collision of hadrons,  then hadronization of the photon plasma occurs instantly giving new mostly unstable ad hoc formations of photons (hadrons),  these hadrons then decay due to their random ad hoc origination,  and from this,  successive instant re-hadronization to other particles from the re-emitted photons occurs,  and/or re-emitted photons do not re-form and leave the interaction area.  Examination of current theory and proposed dynamic models of hadrons consistent with hydrodynamic theory, geometric scaling, and experimental results are given in the attached link.

Article Hadronization of Scattered Particles in High-Energy Impacts