Mirror Matter
Posted by Mirror on Sep 28, 2003 at 05:47
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Experimental implications of mirror matter-type dark matter
R. Foot
Mirror matter-type dark matter is one dark matter candidate which is particularly well motivated from high energy physics. The theoretical motivation and experimental evidence are pedagogically reviewed, with emphasis on the implications of recent orthopositronium experiments, the DAMA/NaI dark matter search, anomalous meteorite events etc.
Implications of the DAMA and CRESST experiments for mirror matter-type dark matter
R. Foot
Mirror atoms are expected to be a significant component of the galactic dark matter halo if mirror matter is identified with the non-baryonic dark matter in the Universe. Mirror matter can interact with ordinary matter via gravity and via the photon-mirror photon kinetic mixing interaction -- causing mirror charged particles to couple to ordinary photons with effective electric charge $\epsilon e$. This means that the nuclei of mirror atoms can elastically scatter off the nuclei of ordinary atoms, leading to nuclear recoils, which can be detected in existing dark matter experiments. We show that the dark matter experiments most sensitive to this type of dark matter candidate (via the nuclear recoil signature) are the DAMA/NaI and CRESST/Sapphire experiments. Furthermore, we show that the impressive annual modulation signal obtained by the DAMA/NaI experiment can be explained by mirror matter-type dark matter for $|\epsilon | \sim 4 \times 10^{-9}$ and is supported by the CRESST/Sapphire data. This value of $|\epsilon |$ is consistent with the value obtained from various solar system anomalies including the Pioneer spacecraft anomaly, anomalous meteorite events and lack of small craters on the asteroid Eros. It is also consistent with standard BBN.
Have mirror micrometeorites been detected?
R. Foot, S. Mitra
Slow-moving ($v \sim 15$ km/s) 'dark matter particles' have allegedly been discovered in a recent experiment. We explore the possibility that these slow moving dark matter particles are small mirror matter dust particles originating from our solar system. Ways of further testing our hypothesis, including the possibility of observing these dust particles in cryogenic detectors such as NAUTILUS, are also discussed.
Detecting mirror matter on Earth via its thermal imprint on ordinary matter
R. Foot, S. Mitra
Mirror matter type dark matter can exist on the Earth's surface, potentially in enhanced concentrations at various anomalous impact sites. Mirror matter fragments can draw in heat from the ordinary matter environment, radiate mirror photons and thereby cool the surrounding ordinary matter. We quantify this effect and suggest that it could be used to help locate mirror matter deposits. This method, together with the centrifuge technique, seems to provide the most promising means to experimentally detect mirror matter type dark matter in the Earth.
Phys.Lett. A315 (2003) 178-183
R. Foot, R. R. Volkas
The cosmological dust has begun to settle. A likely picture is a universe comprised (predominantly) of three components: ordinary baryons ($\Omega_B \approx 0.05$), non-baryonic dark matter ($\Omega_{Dark} \approx 0.22$) and dark energy ($\Omega_{\Lambda} \approx 0.7$). We suggest that the observed similarity of the abundances of ordinary baryons and non-baryonic dark matter ($\Omega_{B}/\Omega_{Dark} \approx 0.20$) hints at an underlying similarity between the fundamental properties of ordinary and dark matter particles. This is necessarily the case if dark matter is identified with mirror matter. We examine a specific mirror matter scenario where $\Omega_B/\Omega_{Dark} \approx 0.20$ is naturally obtained.
Phys.Rev. D68 (2003) 021304
Mirror dark matter and large scale structure
A. Yu. Ignatiev, R. R. Volkas
Mirror matter is a dark matter candidate. In this paper, we re-examine the linear regime of density perturbation growth in a universe containing mirror dark matter. Taking adiabatic scale-invariant perturbations as the input, we confirm that the resulting processed power spectrum is richer than for the more familiar cases of cold, warm and hot dark matter. The new features include a maximum at a certain scale $\lambda_{max}$, collisional damping below a smaller characteristic scale $\lambda'_S$, with oscillatory perturbations between the two. These scales are functions of the fundamental parameters of the theory. In particular, they decrease for decreasing $x$, the ratio of the mirror plasma temperature to that of the ordinary. For $x \sim 0.2$, the scale $\lambda_{max}$ becomes galactic. Mirror dark matter therefore leads to bottom-up large scale structure formation, similar to conventional cold dark matter, for $x \stackrel{<}{\sim} 0.2$. Indeed, the smaller the value of $x$, the closer mirror dark matter resembles standard cold dark matter during the linear regime. The differences pertain to scales smaller than $\lambda'_S$ in the linear regime, and generally in the non-linear regime because mirror dark matter is chemically complex and to some extent dissipative. Lyman-$\alpha$ forest data and the early reionisation epoch established by WMAP may hold the key to distinguishing mirror dark matter from WIMP-style cold dark matter.
Phys.Rev. D68 (2003) 023518
A.Yu.Ignatiev, R.R.Volkas
One of the deepest unsolved puzzles of subatomic physics is why Nature prefers the left particles to the right ones. Mirror matter is an attempt to understand this mystery by assuming the existence of a "parallel''world where this preference is exactly opposite. Thus in the Universe consisting of the ordinary and the mirror matter the symmetry between the left and right is completely restored. Mirror matter is constrained to interact with us only very weakly. Still, its existence can be inferred by using experimental evidence such as the observation of astrophysical objects related to the dark matter (MACHO), neutrino physics and other sources. This talk will focus on several key aspects of mirror matter physics including the possible existence of mirror matter inside the Earth and the suggestion that the recently observed "isolated" planets may in fact be orbiting around mirror stars.
Talk given by A.Yu.Ignatiev at the 15th Biennual Congress of the Australian Institute of Physics (Sydney, July 2002)
Detecting Dark Matter using Centrifuging Techniques
S. Mitra, R. Foot
A new and inexpensive technique for detecting self interacting dark matter in the form of small grains in bulk matter is proposed. Depending on the interactions with ordinary matter, dark matter grains in bulk matter may be isolated by using a centrifuge and using ordinary matter as a filter. The case of mirror matter interacting with ordinary matter via photon-mirror photon kinetic mixing provides a concrete example of this type of dark matter candidate.
Phys. Lett. B558 (2003) 9-14
Mirror matter in the Solar system: New evidence for mirror matter from Eros
R. Foot, S. Mitra
Mirror matter is an entirely new form of matter predicted to exist if mirror symmetry is a fundamental symmetry of nature. Mirror matter has the right broad properties to explain the inferred dark matter of the Universe and might also be responsible for a variety of other puzzles in particle physics, astrophysics, meteoritics and planetary science. It is known that mirror matter can interact with ordinary matter non-gravitationally via photon-mirror photon kinetic mixing. The strength of this possibly fundamental interaction depends on the (theoretically) free parameter $\epsilon$. We consider various proposed manifestations of mirror matter in our solar system examining in particular how the physics changes for different possible values of $\epsilon$. We find new evidence for mirror matter in the solar system coming from the observed sharp reduction in crater rates (for craters less than about 100 meters in diameter) on the asteroid 433 Eros. We also re-examine various existing ideas including the mirror matter explanation for the anomalous meteorite events, anomalous slow-down of Pioneer spacecraft etc.
Astropart. Phys. 19 (2003) 739-753
R. Foot
One of the most fascinating ideas coming from particle physics is the concept of mirror matter. Mirror matter is a new form of matter which is predicted to exist if mirror symmetry is respected by nature. At the preset time evidence that mirror matter actually exists is in abundance, coming from a range of observations and experiments in astronomy, particle physics, meteoritics and planetary science.
Ordinary atom-mirror atom bound states: A new window on the mirror world
R. Foot, S. Mitra
Mirror symmetry is a plausible candidate for a fundamental symmetry of particle interactions which can be exactly conserved if a set of mirror particles exist. The properties of the mirror particles seem to provide an excellent candidate to explain the inferred dark matter of the Universe and might also be responsible for a variety of other puzzles in particle physics, astrophysics, meteoritics and planetary science. One such puzzle -- the orthopositronium lifetime problem -- can be explained if there is a small kinetic mixing of ordinary and mirror photons. We show that this kinetic mixing implies the existence of ordinary atom - mirror atom bound states with interesting terrestrial and astrophysical implications. We suggest that sensitive mass spectroscopic studies of ordinary samples containing heavy elements such as lead might reveal the presence of these bound states, as they would appear as anomalously heavy elements. In addition to the effects of single mirror atoms, collective effects from embedded fragments of mirror matter (such as mirror iron microparticles) are also possible. We speculate that such mirror matter fragments might explain a mysterious UV photon burst observed coming from a laser irradiated lead target in a recent experiment.
Phys.Rev. D66 (2002) 061301
R. Foot, T. L. Yoon
There are a number of very puzzling meteoritic events including (a) The Tunguska event. It is the only known example of a low altitude atmospheric explosion. It is also the largest recorded event. Remarkably no fragments or significant chemical traces have ever been recovered. (b) Anomalous low altitude fireballs which (in some cases) have been observed to hit the ground. The absence of fragments is particularly striking in these cases, but this is not the only reason they are anomalous. On the other hand, there is strong evidence that most of our galaxy is made from exotic dark material - `dark matter'. Mirror matter is one well motivated dark matter candidate, since it is dark and stable and it is required to exist if particle interactions are mirror symmetric. If mirror matter is the dark matter, then some amount must exist in our solar system. We demonstrate that the mirror matter theory allows for a simple explanation for the puzzling meteoritic events [both (a) and (b)] if they are due to mirror matter space-bodies. A direct consequence of this explanation is that mirror matter fragments should exist in (or on) the ground at various impact sites. The properties of this potentially recoverable material depend importantly on the sign of the photon-mirror photon kinetic mixing parameter, $\epsilon$. We argue that the broad characteristics of the anomalous events suggests that $\epsilon$ is probably negative. Strategies for detecting mirror matter in the ground are discussed.
Acta Phys.Polon. B33 (2002) 1979-2009
A mirror world explanation for the Pioneer spacecraft
anomalies?R. Foot, R. R. Volkas
We show that the anomalous acceleration of the Pioneer 10/11 spacecraft can be explained if there is some mirror gas or mirror dust in our solar system.
Phys.Lett. B517 (2001) 13-17
The mirror world interpretation of the 1908 Tunguska event and
other more recent eventsR. Foot
Mirror matter is predicted to exist if parity (i.e. left-right symmetry) is a symmetry of nature. Remarkably mirror matter is capable of simply explaining a large number of contemporary puzzles in astrophysics and particle physics including: Explanation of the MACHO gravitational microlensing events, the existence of close-in extrasolar gas giant planets, apparently `isolated' planets, the solar, atmospheric and LSND neutrino anomalies, the orthopositronium lifetime anomaly and perhaps even gamma ray bursts. One fascinating possibility is that our solar system contains small mirror matter space bodies (asteroid or comet sized objects), which are too small to be revealed from their gravitational effects but nevertheless have explosive implications when they collide with the Earth. We examine the possibility that the 1908 Tunguska explosion in Siberia was the result of the collision of a mirror matter space body with the Earth. We point out that if the catastrophic event and many other similar smaller events are manifestations of the mirror world then these impact sites should be a good place to start digging for mirror matter. Mirror matter could potentially be extracted and purified using a centrifuge and have many useful industrial applications.
Acta Phys.Polon. B32 (2001) 3133
Do mirror planets exist in our solar system?
R. Foot, Z. K. Silagadze
Mirror matter is predicted to exist if parity is an unbroken symmetry of nature. Currently, there is a large amount of evidence that mirror matter actually exists coming from astrophysics and particle physics. One of the most fascinating (but speculative) possibilities is that there is a significant abundance of mirror matter within our solar system. If the mirror matter condensed to form a large body of planatary or stellar mass then there could be interesting observable effects. Indeed studies of long period comets suggest the existence of a solar companion which has escaped direct detection and is therefore a candidate for a mirror body. Nemesis, hypothetical "death star" companion of the Sun, proposed to explain biological mass extinctions, may potentially be a mirror star. We examine the prospects for detecting these objects if they do indeed exist and are made of mirror matter.
Acta Phys.Polon. B32 (2001) 2271-2278
R. Foot
Parity and time reversal are obvious and plausible candidates for fundamental symmetries of nature. Hypothesising that these symmetries exist implies the existence of a new form of matter, called mirror matter. The mirror matter theory (or exact parity model) makes four main predictions: 1) Dark matter in the form of mirror matter should exist in the Universe (i.e. mirror galaxies, stars, planets, meteoroids...), 2) Maximal ordinary neutrino - mirror neutrino oscillations if neutrinos have mass, 3) Orthopositronium should have a shorter effective lifetime than predicted by QED (in "vacuum" experiments) because of the effects of photon-mirror photon mixing and 4) Higgs production and decay rate should be 50% lower than in the standard model due to Higgs mirror - Higgs mixing (assuming that the seperation of the Higgs masses is larger than their decay widths). At the present time there is strong experimental/observational evidence supporting the first three of these predictions, while the fourth one is not tested yet because the Higgs boson, predicted in the standard model of particle physics, is yet to be found. This experimental/observational evidence is rich and varied ranging from the atmospheric and solar neutrino deficits, MACHO gravitational microlensing events, strange properties of extra-solar planets, the existence of "isolated" planets, orthopositronium lifetime anomaly, Tunguska and other strange "meteor" events including perhaps, the origin of the moon. The purpose of this article is to provide a not too technical review of these ideas along with some new results.Acta Phys.Polon. B32 (2001) 2253-2270
Can the mirror world explain the ortho-positronium lifetime
puzzle?R. Foot, S. N. Gninenko
We suggest that the discrepant lifetime measurements of ortho-positronium can be explained by ortho-positronium oscillations into mirror ortho-positronium. This explanation can be tested in future vacuum experiments.Phys.Lett. B480 (2000) 171-175
R. Foot, A. Yu. Ignatiev, R. R. Volkas
The physics of kinetic mixing between ordinary and mirror photons is discussed. An important role is played by four linear combinations we dub the physical photon, the sterile photon, the physical mirror photon, and the sterile mirror photon. Because of the mass degeneracy between the two gauge bosons, quantum coherence effects are important. The physical photon becomes a certain coherent superposition of the bare ordinary photon and the bare mirror photon. Similarly, the physical mirror photon is another, but {\it not orthogonal}, coherent superposition. We discuss the physics of the interaction between physical mirror photons and ordinary matter. Observational signatures for some hybrid ordinary/mirror binary astrophysical systems are qualitatively discussed. We show that a small amount of ordinary matter at the center of a mirror star may make the mirror star observable. We speculate that the recently reported halo white dwarfs might actually be mirror halo stars.Phys.Lett. B503 (2001) 355-361
Have mirror planets been observed?
R. Foot
Over the last few years, several close orbiting ($\sim 0.05$ AU) large mass planets ($M \sim M_{Jupiter}$) of nearby stars have been discovered. Their existence has been inferred from tiny doppler shifts in the light from the star. We suggest that these planets may be made of mirror matter. We also suggest that some stars such as our sun may have a similar amount of mirror matter which has escaped detection.Phys.Lett. B471 (1999) 191-194
Have mirror stars been observed?
R. Foot
Observations by the MACHO collaboration suggest that a significant proportion of the galactic halo dark matter is in the form of compact objects with typical masses $M\sim 0.5M_{\odot}$. One of the current mysteries is the nature and origin of these objects. We suggest that these objects are stars composed of mirror matter. This interpretation provides a plausible explanation for the inferred masses and abundance of the MACHO events. We also comment on the possibility of inferring the existence of mirror supernova's by detecting the neutrino burst in existing underground detectors such as SuperKamiokande.Phys.Lett. B452 (1999) 83-86
The Early Mirror Universe: Inflation, Baryogenesis, Nucleosynthesis and Dark Matter
Zurab Berezhiani, Denis Comelli, Francesco L. Villante
There can exist a parallel `mirror' world which has the same particle physics as the observable world and couples the latter only gravitationally. The nucleosynthesis bounds demand that the mirror sector should have a smaller temperature than the ordinary one. By this reason its evolution should be substantially deviated from the standard cosmology as far as the crucial epochs like baryogenesis, nucleosynthesis etc. are concerned. Starting from an inflationary scenario which could explain the different initial temperatures of the two sectors, we study the time history of the early mirror universe. In particular, we show that in the context of the GUT or electroweak baryogenesis scenarios, the baryon asymmetry in the mirror world should be larger than in the observable one and in fact the mirror baryons could provide the dominant dark matter component of the universe. In addition, analyzing the nucleosynthesis epoch, we show that the mirror helium abundance should be much larger than that of ordinary helium. The implications of the mirror baryons representing a kind of self-interacting dark matter for the large scale structure formation, the CMB anysotropy, the galactic halo structures, microlensing, etc. are briefly discussed.Phys.Lett. B503 (2001) 362-375