Related Experiment Video
Updated: Jan 4, 2026
07:46
Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
8.9K
Can New Physics Hide inside the Proton?
Stefano Carrazza1, Celine Degrande2, Shayan Iranipour3
1Tif Lab, Dipartimento di Fisica, Università di Milano and INFN, Sezione di Milano, Via Celoria 16, I-20133 Milano, Italy.
Physical Review Letters
|November 8, 2019
Summary
This study disentangles beyond the standard model (BSM) dynamics from proton parton distribution functions (PDFs) using deep-inelastic scattering data. It quantifies BSM effects and their impact on PDF fits and SMEFT constraints.
Area of Science:
- Particle Physics
- High-Energy Physics
- Quantum Field Theory
Background:
- Proton structure analyses at high energies probe beyond the Standard Model (BSM) physics.
- Parton distribution functions (PDFs) are crucial for understanding proton structure.
- BSM effects can influence PDF determinations, complicating interpretations.
Purpose of the Study:
- To simultaneously determine proton PDFs and BSM effects.
- To quantify the impact of BSM dynamics on PDF fits.
- To assess how BSM effects modify constraints within the Standard Model Effective Field Theory (SMEFT).
Main Methods:
- Utilized deep-inelastic structure function data.
- Employed the NNPDF framework for simultaneous fitting.
- Considered representative four-fermion operators from SMEFT.
Main Results:
- Successfully disentangled BSM effects from PDFs.
- Quantified the modification of PDFs due to BSM dynamics.
- Assessed the impact of BSM effects on SMEFT parameter bounds.
Conclusions:
- Demonstrated a method to systematically separate BSM physics from proton PDFs.
- Established a framework for joint PDF and BSM determination.
- Improved the precision of SMEFT constraints by accounting for BSM contributions.
Related Concept Videos
03:37Subatomic Particles
111.0K
Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller subatomic particles: protons, neutrons, and electrons. These three particles account for the mass and the charge of an atom.
111.0K
03:18Nuclear Stability
22.7K
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...
22.7K
01:08Atomic Nuclei: Nuclear Spin
4.8K
All atomic particles possess an intrinsic angular momentum, or 'spin'. Electrons, protons, and neutrons each have a spin value of ½, although protons and neutrons in nuclei may have higher half-integer spins owing to energetic factors.
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not contribute to...
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not contribute to...
4.8K
01:33Atomic Structure
205.5K
Overview
205.5K
01:17Atomic Structure
16.2K
The Greek philosopher Democritus proposed that everything on Earth is made up of tiny particles called atomos, Greek for "indivisible," from which the modern term "atom" is derived. In the 19th century, John Dalton proposed the atomic theory that is still largely correct today. He put forth five postulates to explain how atoms made up the world around us. (1) All matter is composed of infinitely small particles or atoms. (2) All atoms of a given element are identical to one...
16.2K
01:03Atomic Nuclei: Nuclear Spin State Overview
1.9K
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of one, the...
1.9K