arXiv subjects

Krzysztof A. Meissner

Publications and source records attributed to Krzysztof A. Meissner.

At least 19 recordsLinked to original sources

arXiv2026

Supermassive charged gravitinos and the Lux-Zeplin event

The Lux-Zeplin collaboration recently reported one unusual event which was interpreted as first evidence for a WIMP (arXiv:2609.02823[hep-ex]). In this note we offer an alternative explanation of this event, following our earlier proposal that dark matter could consist of fractionally charged supermassive gravitinos. A main difference between the two interpretations is that one expects small cross sections and large flux rates for WIMPs, whereas it is the opposite for supermassive gravitinos, namely large (electromagnetic) cross sections and very low flux rates. The observed nuclear recoil energy of about 250 keV and the occurrence of one event in one year fit well with the estimates quoted in (K.A. Meissner, H.~Nicolai, Eur.Phys.J.C 84 (2024) 3, 269). A main characteristic of the new interpretation distinguishing it unequivocally from the WIMP hypothesis would be the sequential occurrence of two or more recoils within a few microseconds along the gravitino's straight trajectory, a prediction that remains to be checked. Such a measurement would also allow to overcome the `neutrino floor'. In this note we refine our previous estimates and propose some extra steps so as to enable the experiment to discriminate between the WIMP and gravitino hypotheses.

hep-ph↗

arXiv2026

Planck mass gravitinos in Einstein-Maxwell backgrounds

Charged massive spin-3/2 fields have long been regarded as problematic, because their coupling to electromagnetism generically leads to loss of hyperbolicity, acausal propagation and loss of unitarity. At the same time, fractionally charged supermassive gravitinos play a central role in a recent proposal of two of the present authors, where they are the only fermionic degrees of freedom beyond the Standard Model and provide novel dark matter candidates. We address this apparent tension by revisiting the result of Deser and Waldron, who showed that the inclusion of gravity can compensate the electromagnetic source of the inconsistency. For a minimally coupled Rarita-Schwinger field in an Einstein-Maxwell background, consistency requires a lower bound on the mass in terms of the charge and the cosmological constant. What is usually a severe obstruction to low-energy charged spin-3/2 phenomenology becomes an independent indication that such particles must lie close to the Planck scale, as argued by two of the present authors on other grounds. We rederive the inequality from the solvability of the Rarita-Schwinger constraints and from the characteristic determinant, emphasizing how the Einstein-Maxwell stress tensor compensates the purely electromagnetic pathology. We then reformulate the system using a Stückelberg spinor, showing that the helicity-1/2 sector reproduces the same condition. This formulation is also essential for obtaining a renormalizable propagator. We discuss this propagator and the corresponding ghost system.

hep-th↗

arXiv2025

The Physics of Conformal Cyclic Cosmology

According to conformal cyclic cosmology (CCC), the currently conventional description of the entire history of the universe (but without an initial inflationary phase) provides but one cosmic aeon of an unending sequence of such aeons, where the future conformal infinity of each aeon joins essentially smoothly to the conformally stretched big bang of the next, across a spacelike 3-surface, referred to as a crossover 3-surface. Whereas in previous accounts of CCC a detailed description of the physics of crossover had been somewhat problematic, a novel idea is introduced here to show how crossover takes place naturally during a temporal period of the universe that is dominated by gravitational waves referred to here as a gravitational wave epoch (GWE). Accordingly, the geometry at the crossover surface is conformally smooth, except at a discrete set of points, referred to as Hawking points, each representing the final Hawking evaporation of the dominant black hole of a galactic cluster in the earlier aeon. It is shown here (using 2-spinor and twistor techniques) that there is a mass-energy conservation law that holds across the crossover surface, showing that the rise of temperature within such Hawking spots should be effectively determined by the total mass of the pre-crossover galactic cluster involved. This rise of temperature on the CMB map within Hawking spots is found to be in quantitative agreement with the masses of the largest galactic clusters observed in our own aeon what suggests that the physics in the previous aeon was, at least in the gravitational sector, similar to ours. A second observational feature, the actual angular diameter of the Hawking spots seen in our CMB, which is about twice what should have been expected, is associated to the presence of GWE just after the crossover and before the start of the usual cosmological epochs.

gr-qc↗

arXiv2025

Standard Model Symmetries and K(E_10)

We clarify and extend our earlier work (K.A.Meissner and H.Nicolai, Phys. Rev. D91 (2015) 065029 and Phys. Rev. Lett. 121 (2018) 091601) where it was shown how to amend a scheme originally proposed by M. Gell-Mann to identify the three families of quarks and leptons of the Standard Model with the 48 spin 1/2 fermions of N=8 supergravity that remain after absorption of eight Goldstinos, a scheme that in its original form is dynamically realized at the SU(3)xU(1) stationary point of gauged N=8 supergravity. We explain how to deform and enlarge this symmetry at the kinematical level to the full Standard Model symmetry group SU(3)_c x SU(2)_w x U(1)_Y, with the correct charge and chiral assignments for all fermions. The framework also leaves room for an extra U(1)_(B-L) symmetry. This symmetry enhancement is achieved by embedding the Standard Model symmetries into (a quotient group of) K(E_10), the `maximal compact subgroup' of the maximal rank hyperbolic Kac-Moody symmetry E_10, and an infinite prolongation of the SU(8) R-symmetry of N=8 supergravity. This scheme, which is also supposed to encompass quantum gravity, cannot be realized within the framework of space-time based (quantum) field theory, but requires space-time and related geometrical concepts to be `emergent'. We critically review the main hypotheses underlying this construction.

hep-th↗

arXiv2024

Signatures of supermassive charged gravitinos in liquid scintillator detectors

In a previous work [K.A. Meissner and H. Nicolai, Eur. Phys. J. C {\bf 84}, 269 (2024)], two of the present authors have suggested possible experimental ways to search for stable supermassive particles with electric charges of $\cO(1)$ in upcoming underground experiments, in particular the new Jiangmen Underground Neutrino Observatory (JUNO) experiment. In the current paper, we present a detailed analysis of the specific signature of such gravitino-induced events for the JUNO detector and for upcoming liquid argon detectors like DUNE (Deep Underground Neutrino Experiment). The proposed method of detection relies on the ``glow'' produced by photons during the passage of such particles through the detector liquid, which would last for about a few to a few hundred microseconds depending on its velocity and the track. The cross sections for electronic excitation of the main component of the scintillator liquid, namely linear alkylbenzene (LAB), by the passing gravitino are evaluated using quantum-chemical methods. The results show that, if such particles exist, the resulting signals would lead to a unique and unmistakable signature, for which we present event simulations as they would be seen by the JUNO or DUNE photomultipliers. Our analysis brings together two very different research areas, namely fundamental particles physics and the search for a fundamental theory on the one hand, and methods of advanced quantum chemistry on the other.

hep-ph↗

arXiv2023

Searching for supermassive charged gravitinos in underground experiments

We examine possible experimental signatures that may be exploited to search for stable supermassive particles with electric charges of $O(1)$ in future underground experiments, and the upcoming JUNO experiment in particular. The telltale signal providing a unique signature of such particles, would be a correlated sequence of three or more nuclear recoils along a straight line, corresponding to the motion of a non-relativistic ($β\lesssim 10^{-2}$) particle that could enter the detector from any direction. We provide some preliminary estimates for the expected event rates.

hep-ph↗

arXiv2023

Fundamental Membranes and the String Dilaton

We study the quantization of the bosonic sector of supermembrane theory in double dimensional reduction, in order to extract the dependence of the resulting world-sheet action on the string dilaton (which cannot be obtained from a purely kinematic reduction). Our construction relies on a Polyakov-type approach with all six metric components on the world-volume as independent quantum fields, and shows that the correct and unique answer is only obtained if the target-space dimension of the theory is restricted to the critical value ($D=11$ for the supermembrane). As a corollary, our analysis implies that there are no analogs of the non-critical string for (super-)membrane theory.

hep-th↗

arXiv2023

A stable supermassive charged gravitino?

Some time ago it was suggested that dark matter may consist in part of an extremely dilute gas of supermassive gravitinos with fractional charge 2$e$/3 \cite{MeissnerNicolai2019}. This scheme makes the definite (and falsifiable) prediction that massive gravitinos are the {\em only} new fermionic degrees of freedom beyond the known three generations of quarks and leptons of the Standard Model of Particle Physics. In this note we re-examine one special outlier event reported and subsequently discarded by the MACRO collaboration \cite{MACRO1} in the light of this proposal and point out the possibility of an alternative interpretation of this event supporting the above hypothesis, whose confirmation (or refutation) would, however, require an independent dedicated experimental effort.

hep-ph↗

arXiv2023

Stability of the de-Sitter spacetime. The anisotropic case

We elaborate on the cosmological implications of the recently established non-perturbative $O(D,D$)-symmetric approach. Following the $α'$-complete Friedmann equations, we provide a qualitative description of the dynamics of anisotropy perturbations. We find that the spacetime stability depends on the sign of the generalized dilaton time derivative. We consider isotropic limits and find possible mechanism for pre-big bang cosmology, governed by the value of cosmological constant.

hep-th↗

arXiv2022

Stability of the non-perturbative $O(D,D)$ de-Sitter spacetime. The isotropic case

The existence of de-Sitter solutions and their stability within string theory became, in recent years, one of the central research questions within the string theory community. The so-called de-Sitter conjecture states that the de-Sitter vacua are unstable within string theory. Here, we study the de-Sitter solutions in string theory and their stability in the time direction using the $O(d,d)$ symmetry approach allowing for the calculation of the generic form of the string theory effective action. We study the undiscussed case of the constant generalized dilaton as well as the general form of dilaton couplings. Our findings suggest that de-Sitter solutions are unstable for the constant generalized dilaton both with and without matter. Furthermore, we found that in order for the theory to be weakly coupled the general form of dilaton coupling is in the form of a cosmological constant.

hep-th↗

arXiv2022

Apparent evidence for Hawking points in the CMB Sky

This paper presents strong observational evidence of numerous previously unobserved anomalous circular spots, of significantly raised temperature, in the CMB sky. The spots have angular radii between 0.03 and 0.04 radians (i.e. angular diameters between about 3 and 4 degrees). There is a clear cut-off at that size, indicating that each anomalous spot would have originated from a highly energetic point-like source, located at the end of inflation -- or else point-like at the conformally expanded Big Bang, if it is considered that there was no inflationary phase. The significant presence of these anomalous spots, was initially noticed in the Planck 70 GHz satellite data by comparison with 1000 standard simulations, and then confirmed by extending the comparison to 10000 simulations. Such anomalous points were then found at precisely the same locations in the WMAP data, their significance confirmed by comparison with 1000 WMAP simulations. Planck and WMAP have very different noise properties and it seems exceedingly unlikely that the observed presence of anomalous points in the same directions on both maps may come entirely from the noise. Subsequently, further confirmation was found in the Planck data by comparison with 1000 FFP8.1 MC simulations (with $l \leq 1500$). The existence of such anomalous regions, resulting from point-like sources at the conformally stretched-out big bang, is a predicted consequence of conformal cyclic cosmology (CCC), these sources being the Hawking points of the theory, resulting from the Hawking radiation from supermassive black holes in a cosmic aeon prior to our own.

astro-ph.CO↗

arXiv2021

Origin and growth of primordial black holes

Building on the insight that primordial black holes can arise from the formation and subsequent gravitational collapse of bound states of stable supermassive elementary particles during the early radiation era, we offer a comprehensive picture describing the evolution and growth of the resulting mini-black holes through both the radiation and matter dominated phases, until the onset of (small scale) inhomogeneities. This is achieved by means of an exact metric solving Einstein's equations throughout both phases. We show that, thanks to a special enhancement effect producing an effective horizon above the actual event horizon, this process can explain the observed mass values of the earliest giant black holes. Unlike other proposals, it also predicts a lower limit on the mass of supermassive black holes.

astro-ph.HE↗

arXiv2021

Asymptotic safety and quantum gravity amplitudes

Application of the Weinberg's conditions of asymptotic safety to amplitudes and not to couplings of the effective action can help to uniquely define the running in the UV and avoid some of the asymptotic safety program problems. The idea is illustrated by the 4-graviton amplitude in string theory and its symmetries.

hep-th↗

arXiv2020

Supermassive gravitinos and giant primordial black holes

We argue that the stable (color singlet) supermassive gravitinos proposed in our previous work can serve as seeds for giant primordial black holes. These seeds are hypothesized to start out as tightly bound states of fractionally charged gravitinos in the radiation dominated era, whose formation is supported by the universally attractive combination of gravitational and electric forces between the gravitinos and anti-gravitinos (reflecting their `almost BPS-like' nature). When lumps of such bound states coalesce and undergo gravitational collapse, the resulting mini-black holes can escape Hawking evaporation if the radiation temperature exceeds the Hawking temperature. Subsequently the black holes evolve according to an exact solution of Einstein's equations, to emerge as macroscopic black holes in the transition to the matter dominated era, with masses on the order of the solar mass or larger. The presence of these seeds at such an early time provides ample time for further accretion of matter and radiation, and would imply the existence of black holes of almost any size in the universe, up to the observed maximum.

astro-ph.HE↗

arXiv2020

Asymptotic safety and Conformal Standard Model

We show that the Conformal Standard Model supplemented with asymptotically safe gravity can be valid up to arbitrarily high energies and give a complete description of particle physics phenomena. We restrict the mass of the second scalar particle to $\sim 300$ GeV and the masses of heavy neutrinos to $\sim 340$ GeV. These predictions can be explicitly tested in the nearby future.

hep-ph↗

arXiv2020

Electron pairs' sliding states in superconductivity

A quantum-mechanical model of Cu-O-Cu-O four-center four-electron part of the copper-oxide plane embedded in a superconducting crystal La$_{2-x}$Sr$% _{x}$CuO$_{4}$ (LSCO) is considered. It is shown that displacing the nearest-neighbor La(Sr)O plane lattice atoms off by a distance as small as $\pm 0.1$ angstrem, i.e. of the order of ground state vibrations dictated by the Heisenberg uncertainty principle, may trigger a dramatic change of the ground state electronic charge distribution in the CuOCuO system. This results in the electron pairs' concerted sliding within the system over distances about 2 angstrem , i.e. close to the copper oxygen atomic distance. The effect depends crucially on the lattice crystal field and doping. The appearance of energy gaps associated with the electronic states' avoided crossings points to a universal nature of the phenomenon. The results suggest a generalization of the models used up to now in description of strongly correlated electrons.

cond-mat.supr-con↗

arXiv2019

Superheavy Gravitinos and Ultra-High Energy Cosmic Rays

We argue that the superheavy gravitinos that we had previously proposed as candidates for Dark Matter can offer a possible explanation for the ultra-high energy cosmic ray (UHECR) events observed at the Pierre Auger Observatory, via gravitino anti-gravitino annihilation in the `skin' of neutron stars. The large mass and strong interactions of these particles, together with their stability against decays into standard matter are essential for the proposed explanation to work. In particular, it ensues that UHECR events can be understood to originate from neutron stars inside a GKZ horizon of $\sim$ 50 Mpc. The composition of neutron stars near their surface could play a crucial role in explaining the presence of heavy ions in these events. If confirmed, this new mechanism can be taken as evidence for the fundamental ansatz towards unification on which it is based.

astro-ph.HE↗

arXiv2019

Planck Mass Charged Gravitino Dark Matter

Following up on our earlier work predicting fractionally charged supermassive gravitinos, we explain their potential relevance as novel candidates for Dark Matter and discuss possible signatures and ways to detect them.

hep-ph↗