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Neutral Particle

Neutral particle is a specific particle with no electrical charge as its algebraic properties inside the neutral particle sum up to zero. A charged particle is on the contrary of particle of no electrical charge and with all its algebraic property opposite to its antiparticle. The properties inside an electrically charged particle is in the opposite way to its antiparticle since their properties inside behaves in the opposite sense. There are two vital ways to recognize the nature of neutral particle. First of all, any non-null algebraic property of a neutral particle such as magnetic moment(Q) in classical physics and quantum number (baryonic number A) reveals the nature of neutral particle. In addition, the decay mode of neutral particle through self-conjugate channels reveals its algebraic properties. These methods imply whether a specific neutral particle itself is likely to be its own antiparticle and thus helps to find whether the decay of the particle is likely to happen [5]. There are 4 main sections in this article, which are description of neutral particles, oscillation of neutral particles, types of neutral particles and application relating to neutral particles. To be specific, there are four subsections inside types of neutral particles, which are Neutrinos and antineutrinos, Meson, Boson.

Description of neutral particles
A famous physician called Rutherford discovered the atomic nucleus in 1911, and observed the proton in 1919. Based on theoretical considerations of the elements of the periodic table, it seems that something in the nucleus exists in addition to protons. For example, helium, the second element of the periodic table, has an atomic number of 2 but a larger mass number of 4, which means there is an extra mass for something inside the nucleus in addition of proton. In 1920, Rutherford proposed that an electron and a proton could combine to form a new neutral particle, however no real evidence was proved for this, and it would be quite difficult for the detection of neutral particle. In 1930, Frederic and Irene conducted an experiment about the radiation from Be, this radiation knocked loose protons from the target hydrogen atoms, and the protons are recoiled with higher velocity. From the experiment, the radiation hitting the target must be in high energy photon due to the conservation of energy(E=1/2mv^2). However, since there is no mass for photons, it wouldn’t knock loose particles in the same weight of proton from the target [7]. In 1932, similar experiments were conducted, and it was convinced that the radiation ejected from beryllium was actually a neutral particle in similar mass as a proton. Several experiments on other targets were also conducted, including helium and lithium, helping to find out that the mass of the helium and lithium was just slightly more than the mass of the proton.

At the same time, an observation of positrons witnessed by Anderson was applied to the concept of antiparticle. It was found that electrons and positrons have the same mass and half-life of particle, which is the same as its antiparticles. From that on, classical physics put forward the ideas of electrical charge and magnetic moment which provides the definition of algebraic quantities opposite to antiparticles. Based on the ideas of electrical charge, Wolfgang Pauli postulated the existence of the neutrino, which is an elementary part of neutral particle. However, both energy and angular momentum were not conserved in the decay mode of neutrino, which seems to be inconsistent with the conservation of physics. Then Pauli additionally pointed out that if a non-interacting, neutral particle was emitted, the conservation laws would be recovered. The first detection of neutrinos did not occur until 1955, when Clyde and Frederic recorded emissions of anti-neutrinos from nuclear reactor [1].

Oscillation of neutral particles
The oscillation of neutral particles is an essential part of physical areas, especially in the research of neutral particles together with their applications. The observable oscillation is specified properly because in the neutral field all conventional charges are trivially zero. The momentum operator was used to determine the oscillation of neutral particles, which is similar to the charge operator for charged fields. In fact, if the momentum operator is defined as the addition of free field and mixed field in physics, it can be found that the total momentum is conserved in time: PA(t) + PB(t) = P1 +P2 = P. The expectation value of the momentum operator at t 6= 0, which is consistent to its initial value. For example, the oscillation of meson is directly related to three different situations of quarks: up and down, charm and strange, and top together with bottom[2].To be specific, building atoms requires up and down quarks and two additional generations such that the existence of these quarks have long half-life properties in quantum physics as they are more massive than up and down quarks but has similar properties to them. In addition, the quartet of oscillating meson pairs contains extra quarks, and the physical action of the weak interaction provides four meson pairs a distinction character than other particles. The characteristic of the oscillated neutral particle depends on two major parameters, and hence difficult for our strategy to detect them. Weak interactions between neutral particles in the momentum operator allow the two kinds of D0 and D¯¯¯ mesons to mix with each other which leads to two new eigenstates of neutral atom with small differences in their masses and lifetimes. These results in oscillations between D0 and D¯¯ with a frequency corporate to the difference in mass [6].

Types of neutral particle
Neutrinos and antineutrinos

The elementary neutral particle is neutrino which plays an essential role in beta-decay process. Since a neutrino has very little mass and is not affected much by the strong nuclear forces. It is difficult to detect neutrinos or use in practical applications as they interact weakly with matters. A neutrino conserves momentum and energy during the decay including emitting positive beta decay (positron, β+) or negative (electron, β−) beta rays. The decay processes exhibit a continuous energy distribution, although both decay processes are linked to transitions discretely. The neutrino occupies several parts of the released energy with the beta particle emission, leading to the continuous energy distribution, because the portion has a huge range from nothing to entire decay energy. Neutrinos are gravitational and weakly interacting subatomic particles with a half unit of spin as antineutrinos are known as the neutrino linked to β− decay, while neutrinos are linked to β+ decay Antineutrons are the antiparticles of neutrinos, which are an basic subatomic particle with little mass and with no extra electrical charge. It belongs to the class of leptons, which indicates they do not interact with strong nuclear force [7]. Specifically, the antineutrino is the counterpart of the neutrino, so that the particles annihilate each other if they exist together at the same location and time [3].

Meson

Mesons are intermediate mass particles making up of a quark-antiquark pairs which are sensitive to the strong force. The theoretical prediction of meson was made by the Japanese physicist Yukawa Hideki in 1935 and the existence of mesons was confirmed in 1947 by the English physicist Cecil Frank Powell’s team with the discovery of the pi-meson. It says that the mesons were not the primary class of cosmic-ray particles as some arguments together with their corresponding experiments indicated that the meson was quite unstable so that they decay into an electron together with other particles (mentioned above neutrino and antineutrino) with an average proper lifetime of 2.2 μ s: It is proved that they must have been produced in the atmosphere together with some electrons being found near sea level regarding to the theory of absorption could mostly have been produced individually by meson decay (such as δ-rays).It is known that so far approximately 200 mesons have been produced and characterized, mostly in high-energy particle-accelerator experiments. A majority of mesons are unstable, with lifetimes ranging from 8-10 second to less than 10−22 second. Mesons are useful tools to study the properties of quark [8].

Boson

Boson is a subatomic particle with integrated spin, which means it has an angular momentum in quantum mechanical units of 0 or 1, governed by the Einstein’s statistics. For example, a photon is a common type of boson which has an angular momentum of 1.It has a limitation of the occupation of same quantum state due to integrated spin. Boson is significantly different from a type of subatomic particles known as fermion because in fermion, there isn’t any limit to the occupation of the same quantum state. For instance, it is known that any object making up of an even number of quarks refers to a boson and any particle making up of an odd number of quarks is a fermion. For example, a proton is comprised of three quarks and therefore it is a fermion. A He atom is made of 2 protons, 2 neutrons and 2 electrons and has a mass number of 4 and therefore it is a boson. In addition, this behavior gives rise, to the specific properties of helium-4 when it is cooled to become a superfluid. There is a specific type of boson called the gauge bosons which can carry force. Nowadays, there are four well-known gauge bosons, which are photons, gluons, W bosons together with Z bosons. However, some predictions are made for theoretical gauge bosons, including gravitons in order to have a further experiment plan of neutral particles[8].

Applications relating to neutral particle
1 Fast neutral particle (FNP) beam sources Fast neutral particle (FNP) beam sources are applicable in the field of the production technology of microelectronic and nano electronic devices to develop the applications of fusion energy. For instance, neutral particle beams heating fusion equipment in the DIII-D National Fusion Facility have been supported by an engineering update that allows changing their energy at a specific time. DIII-D is a tokamak which uses the magnetic moment that contains higher temperature plasmas in order to improve the development of fusion energy [6].

2 Surface cleaning and etching of detectors Surface cleaning and etching of detectors are used directly from beams or by emitting. There are two natural diamond detectors been installed on the National Spherical Torus Experiment (NSTX) in order to have a glance at emitting neutral particles opposite to the neutral beam injection energy. To be specific, time resolved methods have been taken from the neutral particle detectors at different radii. The accurate measurement taken from the neutral particle detector to the vessel relies on the development of a the low-noise preamplifier at a high speed that is superior to the commercial units [6]. In the aim of the more accurate measurement, electromagnetic pick-up noise was decreased to levels which is acceptable.

3 Neutral particle beams that heat fusion plasmas

Neutral particle beams that heat fusion plasmas has been further improved by a system in engineering, which enables them changing their energy from time to time. To be specific, when the particle energy in the beam has been changed, it reduces interactions between electromagnetic plasma waves. As a result, the reduced interactions keep the injected particles in the plasma in a long time and provide more effective heating compared to a fixed energy [9].

Reference
[1] Alksel, H. (1999, September7th). What-is-a-neutrino. Retrieved from: https://www.scientificamerican.com/article/what-is-a-neutrino

[2] Blasone, M. (2003, May 23th). Mixing and oscillations of neutral particles in Quantum Field Theory. High Energy Physics – Phenomenology.D69 (2004) 057301

[3] David, M. （1989）. Neutrons- Comprehensive Polymer Science and Supplements.Retrieved from: https://www.sciencedirect.com/topics/engineering/neutrons

[4] Maishev, Y.P., Shevchuk, S.L., Terent’ev, Y.P. (2015). Installation for etching and deposition of thin-film structures by a fast-neutral particle beam. Russ. Microelectron., vol. 44, no. 5, pp. 304–311.

[5] Prasad A. Naik. (1999). Muonic X-rays. Spectroscopy and Spectrometry.

[6] Revell, P.J. and Evans, A.C. (1981). Ion beam etching using saddle field sources. Thin Solid Films, vol. 86, nos. 2–3, pp. 117–124.

[7] Shiokara, F. (1992). High-power fast-atom beam source and its application to dry etching. J. Vac. Sci. Technol., A, vol. 10, no. 4, pp. 1352–1357.

[8] Shiokara, F. and Nagai, K., A low-energy fast-atom source. (1988). Nuclei. Instron. Methods Phys. Res., Sect. B, vol. 33, nos. 1–4, pp. 867–870

[9] V.P. Kudyra. (2018). Applications of the Technology of Fast Neutral Particle Beams in Micro- and Nanoelectronics. Russian Microelectronics. Pages332–343