相关实验视频
Updated: Jun 22, 2025

07:46
Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
8.6K
使用sqrt[s]=13 TeV的质子对质子碰撞来搜索顶级夸克生成和衰变中的 baryons数违规
A Hayrapetyan1, A Tumasyan1, W Adam2
1Yerevan Physics Institute, Yerevan, Armenia.
Physical review letters
|July 1, 2024
概括
研究人员使用LHC数据在顶级夸克生成和衰变中寻找违反 baryons数的相互作用. 没有发现任何显著的偏差,这导致了顶级夸克衰变过程的新严格约束.
科学领域:
- 高能物理 高能物理
- 粒子物理学 粒子物理学
- 标准模型物理学的标准模型.
背景情况:
- 巴里昂数量违规是一个超越标准模型的关键概念.
- 顶级夸克是新物理学的关键探测器,因为它们的质量很大.
研究的目的:
- 在顶级夸克的产生和衰变中寻找违反 baryons数 (BNV) 相互作用.
- 为了设定BNV合和顶部夸克衰变分支分数的限制.
主要方法:
- 使用CMS探测器对13TeV的质子-质子碰撞数据进行分析.
- 选择两个负荷相反的子和一个底部夸克射流的事件.
- 应用多变量分辨器用于信号与背景的分离.
主要成果:
- 没有观察到与标准模型预测的显著偏差.
- 在BNV合器的强度上设置了上限.
- 通过BNV相互作用进行单顶夸克生成的第一项研究.
结论:
- 这项研究为顶夸克衰变中的BNV相互作用提供了迄今为止最严格的约束.
- 结果提高了之前的边界3到6个数量级.
- 这些发现限制了涉及BNV的新物理模型.
相关概念视频
Nuclear Stability
18.7K
Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together...
To hold positively charged protons together...
18.7K
Nuclear Transmutation
17.5K
Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with another particle. The first manmade nucleus was produced in Ernest Rutherford’s laboratory in 1919 by a transmutation reaction, the bombardment of one type of nuclei with other nuclei or with neutrons. Rutherford bombarded nitrogen-14 atoms with high-speed α particles from a natural radioactive isotope of radium and observed...
17.5K
Types of Radioactivity
16.7K
The most common types of radioactivity are α decay, β decay, γ decay, neutron emission, and electron capture.
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
16.7K
Radioactivity and Nuclear Equations
21.0K
Nuclear chemistry is the study of reactions that involve changes in nuclear structure. The nucleus of an atom is composed of protons and, except for hydrogen, neutrons. The number of protons in the nucleus is called the atomic number (Z) of the element, and the sum of the number of protons and the number of neutrons is the mass number (A). Atoms with the same atomic number but different mass numbers are isotopes of the same element.
A nuclide of an element has a specific number of protons and...
A nuclide of an element has a specific number of protons and...
21.0K
Thomson's e/m Experiment
3.5K
In a beam of charged particles created by a heated cathode, the particles move at different speeds. However, many applications need a beam with uniform particle speeds. An arrangement known as a velocity selector uses electric and magnetic fields to pick particles with a particular speed from the beam.
A particle with charge q, speed v, and mass m enters an area from the top, where the magnetic and electric fields are perpendicular both to the particle's motion and to one another. The...
A particle with charge q, speed v, and mass m enters an area from the top, where the magnetic and electric fields are perpendicular both to the particle's motion and to one another. The...
3.5K
Atomic Number and Mass Number
9.7K
The number of protons in the nucleus of an atom is its atomic number (Z). This is the defining trait of an element. Its value determines the identity of the atom. For example, any atom that contains six protons is the element carbon and has the atomic number 6, regardless of how many neutrons or electrons it may have. A neutral atom must contain the same number of positive and negative charges, so the number of protons equals the number of electrons. This means that the atomic number also...
9.7K

