Posted: Dec 21, 2018
Dark matter is a composition of elements in the universe which are preserved in the form of primordial fluctuations in cosmological density. The existence of dark matter is associated with the formation of supersymmetry prediction of new families of particles which interact weakly with ordinary matter. The growth of dark matter is recorded to have started early that resulted in the formation of galaxies. Dark matter contributed to the provision of gravitational potential in which stable structure in the universe was formed. Dark matter enhanced the existence of galaxies, groups, as well as clusters. The existence of combining forces referred to as the dark energy combined different structures and expanded the space between bound particles that formed structures such as the Local Group of galaxies.
Dark matter determines our existence as well as the future combination of elements. According to dark matter theory, a cosmic inflation has become the basis for the standard model of big bang cosmology called Lambda cold dark matter or Lambda-CDM (?CDM) (Colloquium on the Age of the Universe, Dark Matter, and Structure Formation, 1998). Lambda-CDM is concerned with the formation and existence of cosmic microwave structure data as well as other cosmic rays which include; the distribution of galaxies, high concentration in abundance of hydrogen gas including deuterium, helium, as well as lithium. Dark matter as one of the cosmological density and occupies about 23% of cosmic density. It has the potential of having the dark energy of about that occupies 72%. The baryonic matter occupies up to only about 4.6% while the visible baryons occupy about 0.5% of the cosmic density (Colloquium on the Age of the Universe, Dark Matter, and Structure Formation, 1998).
The Existence of Dark Matter
Initially, the infant universe was characterized by extremely hot, dense, homogeneous mixture of photons and matter. The composition of the universe was tightly coupled together as plasma. The initial characteristics and conditions of this early form of universe plasma are thought to be established long time ago during a period of rapid noncontrolled expansion referred to as inflation. The rapid expansions were contributed by high-density fluctuations within the primordial plasma (International Symposium on Cosmology and Particle Astrophysics, He, & Ng, 2003). The effects were catalyzed by quantum fluctuations within the field of tightly held plasma material which drove the inflation. The high amplitude of the primordial gravitational potential that fluctuated uniformly on all spatial scales led to the formation of small perturbations as new forms of energy.
The small perturbations usually propagate via the plasma collision in the form of a sound wave. It produces under as well as overdensities in the plasma combined with a simultaneous change in density of matter and speed of radiation that influences fluctuation in pressure (International Symposium on Cosmology and Particle Astrophysics, He, & Ng, 2003). However, CDM does not contribute towards sharing pressure induced during the oscillations. It usually acts upon as gravitational forces that either enhances or negates the acoustic patterns of the photons and baryons. The continuous pressure exerted results to initialization of physical conditions that contributes to expansion and rapid cooling of plasma (International Symposium on Cosmology and Particle Astrophysics, He, & Ng, 2003). During the high pressure, the conditions reach a point where electrons, as well as baryons, are capable of gaining stability and recombining. As a result, the state leads to the formation of atoms, commonly in the form of neutral hydrogen. In the process photons finally, decouple from the baryons a condition that leads to the plasma becoming neutral. The formed perturbations cease from propagating as acoustic waves. The preserved and existing density pattern becomes cool and frozen. The cooled and frozen snapshot of the various density fluctuations get preserved within the Cosmic Microwave Background (CMB) anisotropies others get embedded as an imprint of baryon acoustic oscillations (BAO) observable (International Symposium on Cosmology and Particle Astrophysics, He, & Ng, 2003).
The resulting recombination is one associated with the production of large neutral universe characterized by unobservable fields of the electromagnetic spectrum. The period in which the named reactions occur is referred to as the era of dark ages. During the era, some reactions that occur includes CDM beginning gravitational collapse, especially in the overdense regions. Baryonic matter transforms to some gravitational forces that lead to collapsing of the CDM halos and influences the beginning of Cosmic Dawn (International Symposium on Cosmology and Particle Astrophysics, He, & Ng, 2003). The radiations begin with the formation of initial radiation sources such as stars. Produced objects give a lot of radiation that causes other objects to re-ionize through the intergalactic medium. Most of the structures formed to continue to grow to merge other matters under the influence of gravitational pull. The result of the forming materials is a vast cosmic web of dark matter density. The radiating particles cause availability of abundant luminous galaxies that traces the statistics of different underlying matter density. Most of the assembled objects include clusters of galaxies that form the largest bound objects. The reorganization of dark matter results into galaxies that retain the BAO correlation length during the process of formation of CMB energy.With the increase in the dark matter, the universe continues to expand influencing the accumulation of the negative pressure which is associated with the cosmological constant. The constant is in the form of dark matter or dark energy in?CDM (International Symposium on Cosmology and Particle Astrophysics, He, & Ng, 2003). The matter usually increases and dominates over opposing gravitational forces leading to the expansion of the universe.
Types of Dark Matter
The composition of the universe is usually dominated by the cosmic density of both dark energy and dark matter. What the most common physical nature of dark matter remains is yet to be discovered. There are two popular families of dark matter that try to explain about the dark matter particle. They include lightest supersymmetric partner particle also referred to as super-symmetric weakly interacting massive particle (WIMP). A WIMP is one of the weakly interacting dark matter components (Colloquium on the Age of the Universe, Dark Matter, and Structure Formation, 1998). The basic idea behind WIMP particles is that billions of these black matter particles pass human hand within a second. They also pass through the Earth and everything on it. However, WIMPs interact weakly with other particles as well as ordinary matter. Due to their weak interactive reaction, they almost create their impacts entirely unnoticed.
It is a neutrino and is invisible while passing through a typical elementary particle detector. However, through some other properties of the other dark matter particles produced in association with the WIMP, it is possible to recognize their events and select them for analysis. Some of the most specific analysis has been done in models of supersymmetry.
The other particle is the cosmological axion. WIMPs and axions are the most common dark matter particles. Super-symmetry is among the standard models of particles that constitute energy that allows control of vacuum energy as well as used for renormalizing gravitational interactions. It plays a role that allows gravity to be combined with both the weak electronic components as well as strong interactions Super-symmetry dark matter makes it easy and possible for a grand unification of the weak electron materials and brings strong interactions that naturally explain the scaling of smaller particles in the universe. The forces of generated from the gravity lead to the grand unification of Planck scales that leads to solving the gauge hierarchy problem. The establishment of a connection between supersymmetry dark matters breaking with weak-electro symmetry leads to increase in mass that forms a range of about 100 to 1000 GeV (Colloquium on the Age of the Universe, Dark Matter, and Structure Formation, 1998). The state leads to the formation of WIMP cosmological density that maintains balances in the universe. Many other particles including Axion have been indicated as possible dark matter candidates that also follow the principles of supersymmetry (Colloquium on the Age of the Universe, Dark Matter, and Structure Formation, 1998).
Dark matter refers to a term that explains objects available in the universe in the form of the missing mass. It is a standard cosmological event of big bang model. Dark matter interacts with normal matter through the gravity. However, dark matter neither absorbs nor emits radiation and thus making it impossible to be seen. According to big bang cosmologists, they explain that about 25% of the universe is composed of dark matter. The major elements consist of non-standard particles which include neutrinos, axions also known as weakly interacting massive particles WIMPs. About 70% of the known universe is composed of models made up of more obscure dark energy components. The entire composition leaves a 5% of the universe composed of ordinary matter.
Dark Matter (DAMA) Experiment
A remarkable experiment referred to as Dark Matter (DAMA) is well known for using three styles of detectors to facilitate discovering of wimps. The experiment is designed in an exactly similar manner like experiments used in detecting and in the study neutrinos (Cerulli, et. al., 2017). However, DAMA is designed to look for a specific reaction. DAMA is designed to find the energy generated as a result of an interaction with a particular element at a particular angle.
The DAMA experiment has three phases which include processes, having two research and development (R&D) setups as well as one actual experiment that considers the results of the R&D. The basic idea behind DAMA experiment is that since the galaxy rotates at high speed of 232 km/s, the rotation enhances sweeping via the residual CDM material. The study involving the reaction of particles ensures the high possibility of using experiment illustrations to detect the WIMP contents of CDM possibly. The phases are as explained below.
The first phase uses Adhesive silicone CaF4 which is designed to look for a2? decay. The experiment is designed in that format to eliminate known leptons. The phase 1 experiment is set with the intention of determining signs of WIMP detection (Cerulli, et. al., 2017). When the expected results are successful, the second phase is designed as follows
The second phase makes use of isotope of xenon 129Xe; it is used to since it has a high sensitivity that detects R&D. Its superiority allows identifying of three WIMP particles which include photinos, higgsinos, and Majorana Neutrinos (Cerulli, et. al., 2017). After successful results are obtained through detection, the session opens for phase three which involves the actual experiment.
LIBRA – Large Sodium Iodine Bulk for Rare processes
Sodium Iodine (NaI) detectors experiment is set up after the two R&D phases. The results obtained should reveal that the experiment determines the presence of particles that clarify characteristics that qualify particles to be WIMP’s (Cerulli, et. al., 2017).
The DAMA project is a project carried to certainly determine the existence of some particles that resemble the requirements of wimps. The results obtained from DAMA experiment are revealed characteristics of particles such as the mirror symmetry which is a theory of particle physics. As indicated from researchers it is true that every particle of matter has a mirror particle. The experiment reveals that mirror matter particles consist of the sole of CDM (Cerulli, et. al., 2017).
The Large Underground Xenon (LUX) is a dark matter experiment, which is designed to operate underground beneath a mile of rock. It is located in Sanford Underground Research Facility in the Black Hills of South Dakota (Chapman, et al., 2013). The LUX experiment is designed to look for black matter referred to as weakly interacting massive particles (WIMPs). WIMP is considered as the leading theoretical candidate that consists of dark matter particle. The LUX detectors are composed of a third of a ton composed of cooled liquid xenon. It is usually surrounded by powerful sensors which are designed basically for detecting minute and a tiny flash of light (Chapman, et al., 2013). They also detect the electrical charges emitted incase a WIMP particle collides with a xenon atom within the reaction chamber or tank. The detectors are specifically located at Sanford Lab underground one mile of rock. It is usually found inside a 72,000-gallon tank, with a high-purity water tank. The configuration and setup help in shielding it from dangerous cosmic rays as well as effects of other radiation that can easily interfere with a dark matter signals. The scientist makes use of calibration techniques using neutrons as stand-ins for managing and controlling WIMPs particles (Chapman, et al., 2013). The effect is achieved through firing a beam of neutrons in the detectors. By achieving that scientists gain capability of carefully quantifying the process in which LUX detectors responds to the signals produced from a WIMP collision (Chapman, et al., 2013). Other forms of calibration techniques applied include injecting radioactive gasses inside the detecting chamber to help in distinguishing between signals produced during ambient radioactivity as well as potential dark matter signal.
The LUX experiment in South Dakota mine it uses 7 tone of xenon liquid to detect WIMPs
Retrieved from: http://www.sciencemag.org/news/2014/07/two-big-dark-matter-experiments-gain-us-support
CREST-II project Experiment
Another experiment applied for detecting dark matter is the CREST-II project which makes use of Scheelite (CaWO4) using cryogenic detectors. The set up of CREST II project, guarantee complete eliminating of false detection of WIMP using CaWO4 cryogenic detectors through the implementation of background suppression (Overduin, Wesson, & World Scientific (Firm), 2008). The significance of using CaWO4 cryogenic detectors is the ability to detect neutrinos. In this method of detecting dark matter particles, background suppression must be designed in the detector to provide all needed particle detection confirmation that interprets the particle data more effectively (Overduin, Wesson, & World Scientific (Firm), 2008)
Cerulli, R., Villar, P., Cappella, F., Bernabei, R., Belli, P., Incicchitti, A., Addazi, A.,... Berezhiani, Z. (2017). DAMA annual modulation and mirror Dark Matter. The European Physical Journal C : Particles and Fields, 77, 2, 1-20.
Chapman, J. J., Faham, C. H., Fiorucci, S., Gaitskell, R. J., Malling, D. C., Pangilinan, M., Verbus, J. R.,... Pease, E. K. (2013). The Large Underground Xenon (LUX) experiment. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 704, 111-126.
Colloquium on the Age of the Universe, Dark Matter, and Structure Formation. (1998). Colloquium on the Age of the Universe, Dark Matter, and Structure Formation. Washington, D.C: National Academy of Sciences.
International Symposium on Cosmology and Particle Astrophysics, He, X.-G., & Ng, K.-W. (2003). Proceedings of the 2002 International Symposium on Cosmology and Particle Astrophysics: CosPA 2002. River Edge, N.J: World Scientific.
Overduin, J. M., Wesson, P. S., & World Scientific (Firm). (2008). The light/dark universe: Light from galaxies, dark matter and dark energy. Singapore: World Scientific Pub. Co.
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