Luis Gonzalez-Mestres - Profile on Academia.edu (original) (raw)

Papers by Luis Gonzalez-Mestres

Nuclear physics, May 1, 2009

The implications of AUGER and HiRes results for patterns of Lorentz symmetry violation (LSV) are ... more The implications of AUGER and HiRes results for patterns of Lorentz symmetry violation (LSV) are examined, focusing on weak doubly special relativity (WDSR). If the Greisen-Zatsepin-Kuzmin (GZK) cutoff is definitely confirmed, the mass composition of the highest-energy cosmic-ray spectrum will be a crucial issue to draw precise theoretical consequences from the experimental results. Assuming that the observed flux suppression is due to the GZK mechanism, data will allow in principle to exclude a significant range of LSV models and parameters, but other important possibilities are expected to remain open : Lorentz breaking can be weaker or occur at a scale higher than the Planck scale, unconventional LSV effects can fake the GZK cutoff, threshold phenomena can delay its appearance Space experiments appear to be needed to further test special relativity. We also examine the consequences of AUGER and HiRes data for superbradyons. If such superluminal ultimate constituents of matter exist in our Universe, they may provide new forms of dark matter and dark energy.

Epj Web of Conferences, 2014

Detailed analyses of WMAP and Planck data can have significant implications for noncyclic pre-Big... more Detailed analyses of WMAP and Planck data can have significant implications for noncyclic pre-Big Bang approaches incorporating a new fundamental scale beyond the Planck scale and, potentially, new ultimate constituents of matter with unconventional basic properties as compared to standard particles. Cosmic-ray experiments at the highest energies can also yield relevant information. Hopefully, future studies will be able to deal with alternatives: i) to standard physics for the structure of the physical vacuum, the nature of space-time, the validity of quantum field theory and conventional symmetries, the interpretation of string-like theories...; ii) to standard cosmology concerning the origin and evolution of our Universe, unconventional solutions to the cosmological constant problem, the validity of inflationary scenarios, the need for dark matter and dark energy... Lorentz-like symmetries for the properties of matter can then be naturally stable space-time configurations resulting from more general primordial scenarios that incorporate physics beyond the Planck scale and describe the formation and evolution of the physical vacuum. A possible answer to the question of the origin of half-integer spins can be provided by a primordial spinorial space-time with two complex coordinates instead of the conventional four real ones, leading to a really new cosmology. We discuss basic questions and phenomenological topics concerning noncyclic pre-Big Bang cosmologies and potentially related physics.

Nucleation and Atmospheric Aerosols, 2010

Taking into account the experimental results of the HiRes and AUGER collaborations, the present s... more Taking into account the experimental results of the HiRes and AUGER collaborations, the present status of bounds on Lorentz symmetry violation (LSV) patterns is discussed. Although significant constraints will emerge, a wide range of models and values of parameters will still be left open. Cosmological implications of allowed LSV patterns are discussed focusing on the origin of our Universe, the cosmological constant, dark matter and dark energy. Superbradyons (superluminal preons) may be the actual constituents of vacuum and of standard particles, and form equally a cosmological sea leading to new forms of dark matter and dark energy.

arXiv (Cornell University), Mar 1, 2000

Lorentz symmetry violation (LSV) can be generated at the Planck scale, or at some other fundament... more Lorentz symmetry violation (LSV) can be generated at the Planck scale, or at some other fundamental length scale, and naturally preserve Lorentz symmetry as a low-energy limit (deformed Lorentz symmetry, DLS). DLS can have important implications for ultra-high energy cosmic-ray physics (see papers physics/0003080 -hereafter referred to as I -, astro-ph/0011181 and astro-ph/0011182, and references quoted in these papers). A crucial question is how DLS can be extended to a deformed Poincaré symmetry (DPS), and what can be the dynamical origin of this phenomenon. We discuss recent proposals to identify DPS with a symmetry incorporating the Planck scale (doubly special relativity, DSR) and suggest new ways in this direction. Implications for models of quadratically deformed relativistic kinematics (QDRK) and linearly deformed relativistic kinematics (LDRK) are also discussed. This paper updates and further develops some aspects of contributions to the

Nucleation and Atmospheric Aerosols, 2001

Lorentz symmetry violation (LSV) at Planck scale can be tested (see e.g. physics/0003080) through... more Lorentz symmetry violation (LSV) at Planck scale can be tested (see e.g. physics/0003080) through ultra-high energy cosmic rays (UHECR). In a deformed Lorentz symmetry (DLS) pattern where the effective LSV parameter varies like the square of the momentum scale (quadratically deformed relativistic kinematics, QDRK), a ≈ 10 -6 LSV at Planck scale would be enough to produce observable effects on the properties of cosmic rays at the ≈ 10 20 eV scale: absence of GZK cutoff, stability of unstable particles, lower interaction rates, kinematical failure of any parton model and of standard formulae for Lorentz contraction and time dilation... Its phenomenological implications are compatible with existing data. If the effective LSV parameter is taken to vary linearly with the momentum scale (linearly deformed relativistic kinematics, LDRK), a LSV at Planck scale larger than ≈ 10 -7 seems to lead to contradictions with data above ≈ T eV energies. Consequences are important for high-energy gamma-ray experiments, as well as for high-energy cosmic rays and gravitational waves.

HAL (Le Centre pour la Communication Scientifique Directe), Sep 9, 2013

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

The Poincaré relativity principle has been tested at low energy with great accuracy, but its extr... more The Poincaré relativity principle has been tested at low energy with great accuracy, but its extrapolation to very high-energy phenomena is much less well established. Lorentz symmetry can be broken at Planck scale due to the renormalization of gravity or to some deeper structure of matter: we expect such a breaking to be a very high energy and very short distance phenomenon. If textbook special relativity is only an approximate property of the equations describing a sector of matter above some critical distance scale, an absolute local frame (the "vacuum rest frame", VRF) can possibly be found and superluminal sectors of matter may exist related to new degrees of freedom not yet discovered experimentally. The new superluminal particles ("superbradyons", i.e. bradyons with superluminal critical speed) would have positive mass and energy, and behave kinematically like "ordinary" particles (those with critical speed in vacuum equal to c , the speed of light) apart from the difference in critical speed (we expect c i ≫ c , where c i is the critical speed of a superluminal sector). They may be the ultimate building blocks of matter. At speed v > c , they are expected to release "Cherenkov" radiation ("ordinary" particles) in vacuum. Superluminal particles could provide most of the cosmic (dark) matter and produce very high-energy cosmic rays. We discuss: a) the possible relevance of superluminal matter to the composition, sources and spectra of high-energy cosmic rays; b) signatures and experiments allowing to possibly explore such effects. Very large volume and unprecedented background rejection ability are crucial requirements for any detector devoted to the search for cosmic superbradyons. Future cosmic-ray experiments using air-shower detectors (especially from space) naturally fulfil both requirements. "The impossibility to disclose experimentally the absolute motion of the earth seems to be a general law of Nature" H. Poincaré "The interpretation of geometry advocated here cannot be directly applied to submolecular spaces... it might turn out that such an extrapolation is just as incorrect as an extension of the concept of temperature to particles of a solid of molecular dimensions" A. Einstein

Nuclear physics, May 1, 1996

We discuss the possible cosmological implications of a class of superluminal particles, in a scen... more We discuss the possible cosmological implications of a class of superluminal particles, in a scenario where: a) Lorentz invariance is only an approximate property of the equations of a sector of matter; b) several critical speeds of matter in vacuum exist. The Big Bang scenario and the evolution of the very early universe, as well as large scale structure, can be strongly influenced by the new particles.

arXiv (Cornell University), Feb 6, 2012

HAL (Le Centre pour la Communication Scientifique Directe), Mar 28, 2014

The BICEP2 collaboration reports a B-mode polarization of the cosmic microwave background (CMB) r... more The BICEP2 collaboration reports a B-mode polarization of the cosmic microwave background (CMB) radiation inconsistent with the null hypothesis at a significance of > 5 σ. This recent and potentially important result is being often interpreted as a signature of primordial gravitational waves from cosmic inflation. However, the arguments supporting such an interpretation are strictly based on standard cosmology and do not take into account possible new phenomena suggested by Planck data such as the existence of a privileged space direction. In particular, inflation is not needed in pre-Big Bang patterns, and the spinorial space-time (SST) introduced in our 1996-97 papers automatically generates a privileged space direction for each comoving observer. In the presence of this privileged space direction, the existence of CMB B-modes is a natural phenomenon and the signal claimed by BICEP2 would not correspond to any kind of inflationary scenario.

arXiv (Cornell University), Sep 28, 2011

The recent result by the OPERA experiment, confirming a trend already present in a previous resul... more The recent result by the OPERA experiment, confirming a trend already present in a previous result by MINOS, raises the question of a possible strong violation of standard relativity. In particular, the particles of the standard model would have different critical speeds in vacuum, and such differences would be measurable with nowadays facilities. Although several experimental and phenomenological issues remain open, the situation deserves been studied closely from a theoretical point of view. The data cannot be explained by conventional extrapolations of Planck-scale Lorentz symmetry violation (LSV) patterns. But, as already stressed in our previous papers since 1995, a weak mixing of standard particles with superbradyons (particles with positive mass and energy, and a critical speed in vacuum much larger than the speed of light) can explain such an effect. Superbradyons can be the ultimate constituents of matter (superluminal preons), but they may simultaneously exist in our Universe as free particles just as light can cross a transparent material medium. In this case, a direct mixing between superbradyons and the particles of the standard model would be unavoidable. After briefly examining the experimental situation and the problems it may raise, we comment on the possibility of a superbradyonic mixing, as well as on the implications of a spinorial description of space-time where space translations would form a SU(2) compact group.

Epj Web of Conferences, 2016

The development of the statistical bootstrap model for hadrons, quarks and nuclear matter occurre... more The development of the statistical bootstrap model for hadrons, quarks and nuclear matter occurred during the 1960s and the 1970s in a period of exceptional theoretical creativity. And if the transition from hadrons to quarks and gluons as fundamental particles was then operated, a transition from standard particles to preons and from the standard space-time to a spinorial one may now be necessary, including related pre-Big Bang scenarios. We present here a brief historical analysis of the scientific problematic of the 1960s in Particle Physics and of its evolution until the end of the 1970s, including cosmological issues. Particular attention is devoted to the exceptional role of Rolf Hagedorn and to the progress of the statistical boostrap model until the experimental search for the quark-gluon plasma started being considered. In parallel, we simultaneously expose recent results and ideas concerning Particle Physics and in Cosmology, an discuss current open questions. Assuming preons to be constituents of the physical vacuum and the standard particles excitations of this vacuum (the superbradyon hypothesis we introduced in 1995), together with a spinorial space-time (SST), a new kind of Regge trajectories is expected to arise where the angular momentum spacing will be of 1/2 instead of 1. Standard particles can lie on such Regge trajectories inside associated internal symmetry multiplets, and the preonic vacuum structure can generate a new approach to Quantum Field Theory. As superbradyons are superluminal preons, some of the vacuum excitations can have critical speeds larger than the speed of light c, but the cosmological evolution selects by itself the particles with the smallest critical speed (the speed of light). In the new Particle Physics and Cosmology emerging from the pattern thus developed, Hagedornlike temperatures will naturally be present. As new space, time, momentum and energy scales are expected to be generated by the preonic vacuum dynamics, the Planck scale does not necessarily make sense in the new scenario. It also turns out that two potential evidences for a superbradyonic vacuum with a SST geometry exist already: i) the recent results on quantum entanglement at large distances favoring superluminal propagation of signals and correlations ; ii) the anisotropy of the cosmic microwave background radiation between two hemispheres observed by the Planck Collaboration, in agreement with the predictions of cosmic SST automatically generating a privileged space direction for each comoving observer. Simultaneously to the discussion of the large number of open questions, we comment on the required experimental and observational programs. T his paper is dedicated to the memory o f Rol f Hagedorn

arXiv (Cornell University), Aug 28, 1995

arXiv (Cornell University), May 24, 1999

Direct detection of WIMP dark matter candidates has to face many difficult challenges. In particu... more Direct detection of WIMP dark matter candidates has to face many difficult challenges. In particular, it requires an extremely high level of background rejection. The only way out seems to be particle identification which, for experiments based on nucleus recoil, is most efficiently performed by simultaneously detecting ionization or light and phonons. When comparing different approaches, it is necessary to keep in mind the potential requirement of building large detectors and the difficulties that this condition may raise for some cryogenic devices. It is claimed that the luminescent bolometer (simultaneous detection of light and phonons) red by arrays of superconducting tunnel junctions, as proposed by the author some years ago, ultimately provides the most appropriate WIMP detector. Solar neutrino detection and other applications are also briefly discussed.

arXiv (Cornell University), Jul 29, 2004

Non-tachyonic superluminal sectors of matter (superbradyons), with critical speeds in vacuum much... more Non-tachyonic superluminal sectors of matter (superbradyons), with critical speeds in vacuum much larger than the speed of light, can quite naturally exist and play an important role in both cosmic-ray physics (anomalous high-energy events) and cosmology (big-bang physics, alternatives to inflation, dark matter...). They can even be the real "elementary" particles. An updated discussion of the subject is presented, in relation with recent theoretical and experimental results. Prospects for future searches are also reexamined. Lorentz symmetry violation (LSV) models based on mixing with superbradyons are compared with LDRK (linearly deformed relativistic kinematics) and QDRK (quadratically deformed relativistic kinematics) such as defined in our previous paper physics/0003080 .

arXiv (Cornell University), May 24, 1999

Present low-energy bounds on Lorentz symmetry violation do not allow to exclude the possible exis... more Present low-energy bounds on Lorentz symmetry violation do not allow to exclude the possible existence of superluminal particles (superbradyons) with critical speed in vacuum ciggcc_i \gg cciggc (c = speed of light) whose kinematical properties would be close to of "ordinary" particles (bradyons) apart from the difference in critical speed. If they exist, superbradyons may be the basic building blocks of vacuum and and matter at Planck scale, provide most of the matter in the Universe and be natural dark matter candidates. We present an updated discussion of their theoretical and experimental properties, especially as cosmic ray primaries or sources, as well as problems related to their possible direct detection.

arXiv (Cornell University), Jul 29, 2004

Using new theoretical tools, which allow to better understand ultra-high energy (UHE) dynamics, s... more Using new theoretical tools, which allow to better understand ultra-high energy (UHE) dynamics, several patterns of Lorentz symmetry violation (LSV) are studied and compared with experiment. It is claimed that quadratically deformed relativistic kinematics (QDRK), where the parameter driving LSV varies like the square of the energy scale, remains the best suited pattern to describe LSV generated at the Planck scale. Implications of existing data are discussed and prospects are presented having in mind next-generation experiments.

arXiv (Cornell University), May 21, 1999

Lorentz symmetry violation (LSV) is often discussed using models of the THepsilonmuTH\epsilon \mu THepsilonmu type wh... more Lorentz symmetry violation (LSV) is often discussed using models of the THepsilonmuTH\epsilon \mu THepsilonmu type which involve, basically, energy independent parameters. However, if LSV is generated at the Planck scale or at some other fundamental length scale, it can naturally preserve Lorentz symmetry as a low-energy limit (deformed Lorentz symmetry, DLS). Deformed relativistic kinematics (DRK) would be consistent with special relativity in the limit kkk (wave vector) to0˜\to ~0to0˜ and allow for a deformed version of general relativity and gravitation. We present an updated discussion of the possible implications of this pattern for cosmic-ray physics at very high energy. A approx1˜0−6\approx ~10^{-6}approx1˜0−6 LSV at Planck scale, leading to a DLS pattern, would potentially be enough to produce very important observable effects on the properties of cosmic rays at the approx1˜020eV\approx \~10^{20} eVapprox1˜020eV scale (absence of GZK cutoff, stability of unstable particles, lower interaction rates, kinematical failure of the parton model...). We compare our approach with more recent similar claims made by S. Coleman and S. Glashow from models of the THepsilonmuTH\epsilon \muTHepsilonmu type.

arXiv (Cornell University), Oct 27, 2005

Most current models of Lorentz symmetry violation (LSV) at the Planck scale involve power-like ex... more Most current models of Lorentz symmetry violation (LSV) at the Planck scale involve power-like extrapolations of the Lorentz-beaking term down to accelerator and even much lower energies. It is therefore assumed that no intermediate energy scale alters this behaviour. But this is not the only possible scenario: a more sophisticate energy-dependence is possible, and would even be natural, involving significant effective thresholds at intermediate energies. Such thresholds may exist between the Planck scale and the highest cosmic-ray energies, or between ultra-high cosmic-ray energies and the TeV scale, leading to interesting scenarios. In many cases, experimental predictions of LSV patterns can be dramatically modified and space experiments become necessary irrespective of AUGER results. By combining both kinds of experiments, future results of cosmic-ray observations will hopefully be able to test, for a large family of models involving various patterns of Planck-scale physics, the possible existence of an absolute local rest frame in the real world.

Although Lorentz symmetry has been tested at low energy with extremely good accuracy, its validit... more Although Lorentz symmetry has been tested at low energy with extremely good accuracy, its validity at very high energy is much less well established. If Lorentz symmetry violation (LSV) is energy-dependent (e.g. ∝ E 2 ), it can be of order 1 at Planck scale and undetectable at GeV scale or below. Similarly, superluminal particles with positive mass and energy (superbradyons) can exist and be the ultimate building blocks of matter. We discuss a few cosmological consequences of such a scenario, as well as possible experimental tests.

Nuclear physics, May 1, 2009

The implications of AUGER and HiRes results for patterns of Lorentz symmetry violation (LSV) are ... more The implications of AUGER and HiRes results for patterns of Lorentz symmetry violation (LSV) are examined, focusing on weak doubly special relativity (WDSR). If the Greisen-Zatsepin-Kuzmin (GZK) cutoff is definitely confirmed, the mass composition of the highest-energy cosmic-ray spectrum will be a crucial issue to draw precise theoretical consequences from the experimental results. Assuming that the observed flux suppression is due to the GZK mechanism, data will allow in principle to exclude a significant range of LSV models and parameters, but other important possibilities are expected to remain open : Lorentz breaking can be weaker or occur at a scale higher than the Planck scale, unconventional LSV effects can fake the GZK cutoff, threshold phenomena can delay its appearance Space experiments appear to be needed to further test special relativity. We also examine the consequences of AUGER and HiRes data for superbradyons. If such superluminal ultimate constituents of matter exist in our Universe, they may provide new forms of dark matter and dark energy.

Epj Web of Conferences, 2014

Detailed analyses of WMAP and Planck data can have significant implications for noncyclic pre-Big... more Detailed analyses of WMAP and Planck data can have significant implications for noncyclic pre-Big Bang approaches incorporating a new fundamental scale beyond the Planck scale and, potentially, new ultimate constituents of matter with unconventional basic properties as compared to standard particles. Cosmic-ray experiments at the highest energies can also yield relevant information. Hopefully, future studies will be able to deal with alternatives: i) to standard physics for the structure of the physical vacuum, the nature of space-time, the validity of quantum field theory and conventional symmetries, the interpretation of string-like theories...; ii) to standard cosmology concerning the origin and evolution of our Universe, unconventional solutions to the cosmological constant problem, the validity of inflationary scenarios, the need for dark matter and dark energy... Lorentz-like symmetries for the properties of matter can then be naturally stable space-time configurations resulting from more general primordial scenarios that incorporate physics beyond the Planck scale and describe the formation and evolution of the physical vacuum. A possible answer to the question of the origin of half-integer spins can be provided by a primordial spinorial space-time with two complex coordinates instead of the conventional four real ones, leading to a really new cosmology. We discuss basic questions and phenomenological topics concerning noncyclic pre-Big Bang cosmologies and potentially related physics.

Nucleation and Atmospheric Aerosols, 2010

Taking into account the experimental results of the HiRes and AUGER collaborations, the present s... more Taking into account the experimental results of the HiRes and AUGER collaborations, the present status of bounds on Lorentz symmetry violation (LSV) patterns is discussed. Although significant constraints will emerge, a wide range of models and values of parameters will still be left open. Cosmological implications of allowed LSV patterns are discussed focusing on the origin of our Universe, the cosmological constant, dark matter and dark energy. Superbradyons (superluminal preons) may be the actual constituents of vacuum and of standard particles, and form equally a cosmological sea leading to new forms of dark matter and dark energy.

arXiv (Cornell University), Mar 1, 2000

Lorentz symmetry violation (LSV) can be generated at the Planck scale, or at some other fundament... more Lorentz symmetry violation (LSV) can be generated at the Planck scale, or at some other fundamental length scale, and naturally preserve Lorentz symmetry as a low-energy limit (deformed Lorentz symmetry, DLS). DLS can have important implications for ultra-high energy cosmic-ray physics (see papers physics/0003080 -hereafter referred to as I -, astro-ph/0011181 and astro-ph/0011182, and references quoted in these papers). A crucial question is how DLS can be extended to a deformed Poincaré symmetry (DPS), and what can be the dynamical origin of this phenomenon. We discuss recent proposals to identify DPS with a symmetry incorporating the Planck scale (doubly special relativity, DSR) and suggest new ways in this direction. Implications for models of quadratically deformed relativistic kinematics (QDRK) and linearly deformed relativistic kinematics (LDRK) are also discussed. This paper updates and further develops some aspects of contributions to the

Nucleation and Atmospheric Aerosols, 2001

Lorentz symmetry violation (LSV) at Planck scale can be tested (see e.g. physics/0003080) through... more Lorentz symmetry violation (LSV) at Planck scale can be tested (see e.g. physics/0003080) through ultra-high energy cosmic rays (UHECR). In a deformed Lorentz symmetry (DLS) pattern where the effective LSV parameter varies like the square of the momentum scale (quadratically deformed relativistic kinematics, QDRK), a ≈ 10 -6 LSV at Planck scale would be enough to produce observable effects on the properties of cosmic rays at the ≈ 10 20 eV scale: absence of GZK cutoff, stability of unstable particles, lower interaction rates, kinematical failure of any parton model and of standard formulae for Lorentz contraction and time dilation... Its phenomenological implications are compatible with existing data. If the effective LSV parameter is taken to vary linearly with the momentum scale (linearly deformed relativistic kinematics, LDRK), a LSV at Planck scale larger than ≈ 10 -7 seems to lead to contradictions with data above ≈ T eV energies. Consequences are important for high-energy gamma-ray experiments, as well as for high-energy cosmic rays and gravitational waves.

HAL (Le Centre pour la Communication Scientifique Directe), Sep 9, 2013

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

The Poincaré relativity principle has been tested at low energy with great accuracy, but its extr... more The Poincaré relativity principle has been tested at low energy with great accuracy, but its extrapolation to very high-energy phenomena is much less well established. Lorentz symmetry can be broken at Planck scale due to the renormalization of gravity or to some deeper structure of matter: we expect such a breaking to be a very high energy and very short distance phenomenon. If textbook special relativity is only an approximate property of the equations describing a sector of matter above some critical distance scale, an absolute local frame (the "vacuum rest frame", VRF) can possibly be found and superluminal sectors of matter may exist related to new degrees of freedom not yet discovered experimentally. The new superluminal particles ("superbradyons", i.e. bradyons with superluminal critical speed) would have positive mass and energy, and behave kinematically like "ordinary" particles (those with critical speed in vacuum equal to c , the speed of light) apart from the difference in critical speed (we expect c i ≫ c , where c i is the critical speed of a superluminal sector). They may be the ultimate building blocks of matter. At speed v > c , they are expected to release "Cherenkov" radiation ("ordinary" particles) in vacuum. Superluminal particles could provide most of the cosmic (dark) matter and produce very high-energy cosmic rays. We discuss: a) the possible relevance of superluminal matter to the composition, sources and spectra of high-energy cosmic rays; b) signatures and experiments allowing to possibly explore such effects. Very large volume and unprecedented background rejection ability are crucial requirements for any detector devoted to the search for cosmic superbradyons. Future cosmic-ray experiments using air-shower detectors (especially from space) naturally fulfil both requirements. "The impossibility to disclose experimentally the absolute motion of the earth seems to be a general law of Nature" H. Poincaré "The interpretation of geometry advocated here cannot be directly applied to submolecular spaces... it might turn out that such an extrapolation is just as incorrect as an extension of the concept of temperature to particles of a solid of molecular dimensions" A. Einstein

Nuclear physics, May 1, 1996

We discuss the possible cosmological implications of a class of superluminal particles, in a scen... more We discuss the possible cosmological implications of a class of superluminal particles, in a scenario where: a) Lorentz invariance is only an approximate property of the equations of a sector of matter; b) several critical speeds of matter in vacuum exist. The Big Bang scenario and the evolution of the very early universe, as well as large scale structure, can be strongly influenced by the new particles.

arXiv (Cornell University), Feb 6, 2012

HAL (Le Centre pour la Communication Scientifique Directe), Mar 28, 2014

The BICEP2 collaboration reports a B-mode polarization of the cosmic microwave background (CMB) r... more The BICEP2 collaboration reports a B-mode polarization of the cosmic microwave background (CMB) radiation inconsistent with the null hypothesis at a significance of > 5 σ. This recent and potentially important result is being often interpreted as a signature of primordial gravitational waves from cosmic inflation. However, the arguments supporting such an interpretation are strictly based on standard cosmology and do not take into account possible new phenomena suggested by Planck data such as the existence of a privileged space direction. In particular, inflation is not needed in pre-Big Bang patterns, and the spinorial space-time (SST) introduced in our 1996-97 papers automatically generates a privileged space direction for each comoving observer. In the presence of this privileged space direction, the existence of CMB B-modes is a natural phenomenon and the signal claimed by BICEP2 would not correspond to any kind of inflationary scenario.

arXiv (Cornell University), Sep 28, 2011

The recent result by the OPERA experiment, confirming a trend already present in a previous resul... more The recent result by the OPERA experiment, confirming a trend already present in a previous result by MINOS, raises the question of a possible strong violation of standard relativity. In particular, the particles of the standard model would have different critical speeds in vacuum, and such differences would be measurable with nowadays facilities. Although several experimental and phenomenological issues remain open, the situation deserves been studied closely from a theoretical point of view. The data cannot be explained by conventional extrapolations of Planck-scale Lorentz symmetry violation (LSV) patterns. But, as already stressed in our previous papers since 1995, a weak mixing of standard particles with superbradyons (particles with positive mass and energy, and a critical speed in vacuum much larger than the speed of light) can explain such an effect. Superbradyons can be the ultimate constituents of matter (superluminal preons), but they may simultaneously exist in our Universe as free particles just as light can cross a transparent material medium. In this case, a direct mixing between superbradyons and the particles of the standard model would be unavoidable. After briefly examining the experimental situation and the problems it may raise, we comment on the possibility of a superbradyonic mixing, as well as on the implications of a spinorial description of space-time where space translations would form a SU(2) compact group.

Epj Web of Conferences, 2016

The development of the statistical bootstrap model for hadrons, quarks and nuclear matter occurre... more The development of the statistical bootstrap model for hadrons, quarks and nuclear matter occurred during the 1960s and the 1970s in a period of exceptional theoretical creativity. And if the transition from hadrons to quarks and gluons as fundamental particles was then operated, a transition from standard particles to preons and from the standard space-time to a spinorial one may now be necessary, including related pre-Big Bang scenarios. We present here a brief historical analysis of the scientific problematic of the 1960s in Particle Physics and of its evolution until the end of the 1970s, including cosmological issues. Particular attention is devoted to the exceptional role of Rolf Hagedorn and to the progress of the statistical boostrap model until the experimental search for the quark-gluon plasma started being considered. In parallel, we simultaneously expose recent results and ideas concerning Particle Physics and in Cosmology, an discuss current open questions. Assuming preons to be constituents of the physical vacuum and the standard particles excitations of this vacuum (the superbradyon hypothesis we introduced in 1995), together with a spinorial space-time (SST), a new kind of Regge trajectories is expected to arise where the angular momentum spacing will be of 1/2 instead of 1. Standard particles can lie on such Regge trajectories inside associated internal symmetry multiplets, and the preonic vacuum structure can generate a new approach to Quantum Field Theory. As superbradyons are superluminal preons, some of the vacuum excitations can have critical speeds larger than the speed of light c, but the cosmological evolution selects by itself the particles with the smallest critical speed (the speed of light). In the new Particle Physics and Cosmology emerging from the pattern thus developed, Hagedornlike temperatures will naturally be present. As new space, time, momentum and energy scales are expected to be generated by the preonic vacuum dynamics, the Planck scale does not necessarily make sense in the new scenario. It also turns out that two potential evidences for a superbradyonic vacuum with a SST geometry exist already: i) the recent results on quantum entanglement at large distances favoring superluminal propagation of signals and correlations ; ii) the anisotropy of the cosmic microwave background radiation between two hemispheres observed by the Planck Collaboration, in agreement with the predictions of cosmic SST automatically generating a privileged space direction for each comoving observer. Simultaneously to the discussion of the large number of open questions, we comment on the required experimental and observational programs. T his paper is dedicated to the memory o f Rol f Hagedorn

arXiv (Cornell University), Aug 28, 1995

arXiv (Cornell University), May 24, 1999

Direct detection of WIMP dark matter candidates has to face many difficult challenges. In particu... more Direct detection of WIMP dark matter candidates has to face many difficult challenges. In particular, it requires an extremely high level of background rejection. The only way out seems to be particle identification which, for experiments based on nucleus recoil, is most efficiently performed by simultaneously detecting ionization or light and phonons. When comparing different approaches, it is necessary to keep in mind the potential requirement of building large detectors and the difficulties that this condition may raise for some cryogenic devices. It is claimed that the luminescent bolometer (simultaneous detection of light and phonons) red by arrays of superconducting tunnel junctions, as proposed by the author some years ago, ultimately provides the most appropriate WIMP detector. Solar neutrino detection and other applications are also briefly discussed.

arXiv (Cornell University), Jul 29, 2004

Non-tachyonic superluminal sectors of matter (superbradyons), with critical speeds in vacuum much... more Non-tachyonic superluminal sectors of matter (superbradyons), with critical speeds in vacuum much larger than the speed of light, can quite naturally exist and play an important role in both cosmic-ray physics (anomalous high-energy events) and cosmology (big-bang physics, alternatives to inflation, dark matter...). They can even be the real "elementary" particles. An updated discussion of the subject is presented, in relation with recent theoretical and experimental results. Prospects for future searches are also reexamined. Lorentz symmetry violation (LSV) models based on mixing with superbradyons are compared with LDRK (linearly deformed relativistic kinematics) and QDRK (quadratically deformed relativistic kinematics) such as defined in our previous paper physics/0003080 .

arXiv (Cornell University), May 24, 1999

Present low-energy bounds on Lorentz symmetry violation do not allow to exclude the possible exis... more Present low-energy bounds on Lorentz symmetry violation do not allow to exclude the possible existence of superluminal particles (superbradyons) with critical speed in vacuum ciggcc_i \gg cciggc (c = speed of light) whose kinematical properties would be close to of "ordinary" particles (bradyons) apart from the difference in critical speed. If they exist, superbradyons may be the basic building blocks of vacuum and and matter at Planck scale, provide most of the matter in the Universe and be natural dark matter candidates. We present an updated discussion of their theoretical and experimental properties, especially as cosmic ray primaries or sources, as well as problems related to their possible direct detection.

arXiv (Cornell University), Jul 29, 2004

Using new theoretical tools, which allow to better understand ultra-high energy (UHE) dynamics, s... more Using new theoretical tools, which allow to better understand ultra-high energy (UHE) dynamics, several patterns of Lorentz symmetry violation (LSV) are studied and compared with experiment. It is claimed that quadratically deformed relativistic kinematics (QDRK), where the parameter driving LSV varies like the square of the energy scale, remains the best suited pattern to describe LSV generated at the Planck scale. Implications of existing data are discussed and prospects are presented having in mind next-generation experiments.

arXiv (Cornell University), May 21, 1999

Lorentz symmetry violation (LSV) is often discussed using models of the THepsilonmuTH\epsilon \mu THepsilonmu type wh... more Lorentz symmetry violation (LSV) is often discussed using models of the THepsilonmuTH\epsilon \mu THepsilonmu type which involve, basically, energy independent parameters. However, if LSV is generated at the Planck scale or at some other fundamental length scale, it can naturally preserve Lorentz symmetry as a low-energy limit (deformed Lorentz symmetry, DLS). Deformed relativistic kinematics (DRK) would be consistent with special relativity in the limit kkk (wave vector) to0˜\to ~0to0˜ and allow for a deformed version of general relativity and gravitation. We present an updated discussion of the possible implications of this pattern for cosmic-ray physics at very high energy. A approx1˜0−6\approx ~10^{-6}approx1˜0−6 LSV at Planck scale, leading to a DLS pattern, would potentially be enough to produce very important observable effects on the properties of cosmic rays at the approx1˜020eV\approx \~10^{20} eVapprox1˜020eV scale (absence of GZK cutoff, stability of unstable particles, lower interaction rates, kinematical failure of the parton model...). We compare our approach with more recent similar claims made by S. Coleman and S. Glashow from models of the THepsilonmuTH\epsilon \muTHepsilonmu type.

arXiv (Cornell University), Oct 27, 2005

Most current models of Lorentz symmetry violation (LSV) at the Planck scale involve power-like ex... more Most current models of Lorentz symmetry violation (LSV) at the Planck scale involve power-like extrapolations of the Lorentz-beaking term down to accelerator and even much lower energies. It is therefore assumed that no intermediate energy scale alters this behaviour. But this is not the only possible scenario: a more sophisticate energy-dependence is possible, and would even be natural, involving significant effective thresholds at intermediate energies. Such thresholds may exist between the Planck scale and the highest cosmic-ray energies, or between ultra-high cosmic-ray energies and the TeV scale, leading to interesting scenarios. In many cases, experimental predictions of LSV patterns can be dramatically modified and space experiments become necessary irrespective of AUGER results. By combining both kinds of experiments, future results of cosmic-ray observations will hopefully be able to test, for a large family of models involving various patterns of Planck-scale physics, the possible existence of an absolute local rest frame in the real world.

Although Lorentz symmetry has been tested at low energy with extremely good accuracy, its validit... more Although Lorentz symmetry has been tested at low energy with extremely good accuracy, its validity at very high energy is much less well established. If Lorentz symmetry violation (LSV) is energy-dependent (e.g. ∝ E 2 ), it can be of order 1 at Planck scale and undetectable at GeV scale or below. Similarly, superluminal particles with positive mass and energy (superbradyons) can exist and be the ultimate building blocks of matter. We discuss a few cosmological consequences of such a scenario, as well as possible experimental tests.