Related Experiment Video
Updated: Apr 21, 2026
05:51
Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
Published on: July 19, 2019
5.8K
Evidence for CP violation in B+ → ppK+ decays.
R Aaij1, B Adeva2, M Adinolfi3
1Nikhef National Institute for Subatomic Physics, Amsterdam, The Netherlands.
Physical Review Letters
|October 18, 2014
Summary
Researchers observed CP violation in B+ to ppK+ decays, a significant finding for baryonic final states. This study also measured forward-backward asymmetry and branching fractions for related B+ decays.
Area of Science:
- Particle Physics
- High-Energy Physics
- Quantum Chromodynamics
Background:
- The Standard Model of particle physics describes fundamental particles and forces.
- B meson decays provide a rich laboratory for testing the Standard Model and searching for new physics.
- Understanding CP violation in baryonic decays is crucial for explaining the matter-antimatter asymmetry in the universe.
Purpose of the Study:
- To investigate three-body decays of the B+ meson, specifically B+ → ppK+ and B+ → ppπ+.
- To search for and measure CP violation in these decays, particularly in the B+ → ppK+ channel.
- To measure the forward-backward asymmetry of the light meson and the branching fraction of B+ → Λ(1520)p.
Main Methods:
- Analysis of a large dataset (3.0 fb⁻¹) from proton-proton collisions at 7 and 8 TeV collected by the LHCb experiment.
- Selection and reconstruction of B+ → ppK+ and B+ → ppπ+ decay candidates.
- Phase-space dependent measurements of asymmetries and branching fractions.
Main Results:
- Evidence of CP violation was found in the B+ → ppK+ decay within specific phase-space regions.
- The first measurement of CP violation in a baryonic final state was achieved.
- Forward-backward asymmetry measurements: A(FB)(ppK+, m(pp)<2.85 GeV/c²) = 0.495 ± 0.012 (stat) ± 0.007 (syst) and A(FB)(ppπ+, m(pp)<2.85 GeV/c²) = -0.409 ± 0.033 (stat) ± 0.006 (syst).
- The branching fraction for B+ → Λ(1520)p was measured as (3.15 ± 0.48 (stat) ± 0.07 (syst) ± 0.26 (BF)) × 10⁻⁷.
Conclusions:
- The observation of CP violation in B+ → ppK+ decays opens new avenues for studying this phenomenon in baryonic systems.
- These measurements provide valuable data for theoretical models aiming to explain CP violation and the matter-antimatter asymmetry.
- The precise measurement of branching fractions contributes to a more comprehensive understanding of B meson decay modes.
Related Concept Videos
01:04¹³C NMR: ¹H–¹³C Decoupling
1.7K
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
1.7K
01:12Double Resonance Techniques: Overview
856
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
856
03:23Types of Radioactivity
15.4K
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:
15.4K
01:19Thomson's e/m Experiment
8.1K
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 magnetic...
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 magnetic...
8.1K
01:20¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
1.3K
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
1.3K
01:14Atomic Nuclei: Nuclear Spin State Population Distribution
1.7K
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
1.7K