# Experimental particle physics

Experimental particle physics is the practical investigation of the fundamental components of matter and radiation. A crucial tool in the arsenal of the experimental particle physicist is the particle accelerator. The fundamental particles that make up matter can briefly be revealed when matter collides together at speeds close to that of light.

## Featured

• News & Views |

### A tetraquark trophy

• Zhiqing Liu

## Latest Research and Reviews

• Research
| Open Access

• Hiroyuki K. M. Tanaka
Scientific Reports 12, 10114
• Research
| Open Access

### Observation of an exotic narrow doubly charmed tetraquark

The LHCb Collaboration reports the observation of an exotic, narrow, tetraquark state that contains two charm quarks, an up antiquark and a down antiquark.

• R. Aaij
• , A. S. W. Abdelmotteleb
•  & G. Zunica
• Research
| Open Access

### Study of the doubly charmed tetraquark $${{{{{{\rm{T}}}}}}}_{{{{{{\rm{c}}}}}}{{{{{\rm{c}}}}}}}^{+}$$

The existence and properties of tetraquark states with two heavy quarks and two light antiquarks have been widely debated. Here, the authors use a unitarized model to study the properties of an exotic narrow state compatible with a doubly charmed tetraquark.

• R. Aaij
• , A. S. W. Abdelmotteleb
•  & G. Zunica
• Research
| Open Access

### In-situ γ-ray analysis of ground surface radioactivity using portable HPGe γ spectrometer

• Zeqian Wu
• , Bairong Wang
•  & Changwei Zhao
• Research
| Open Access

### Probing CP symmetry and weak phases with entangled double-strange baryons

Using spin-entangled baryon–antibaryon pairs, the BESIII Collaboration reports on high-precision measurements of potential charge conjugation and parity (CP)-symmetry-violating effects in hadrons.

• M. Ablikim
• , M. N. Achasov
•  & J. H. Zou
Nature 606, 64-69
• Research
| Open Access

### Convolutional neural network-based reconstruction for positronium annihilation localization

• Jin Jegal
• , Dongwoo Jeong
•  & Hongjoo Kim

## News and Comment

• News & Views |

### A tetraquark trophy

The hunt for new particles helps to complete our understanding of hadronic matter. The LHCb Collaboration now reports the surprising observation of a doubly charmed tetraquark.

• Zhiqing Liu
• News & Views |

### Watch out for the W

• Stefanie Reichert
Nature Physics 18, 486
• Research Highlights |

### Quantum searches for dark matter

Two recent studies report more stringent constraints on dark matter from experiments with atoms and ions that make use of techniques and devices developed for quantum technologies.

• Iulia Georgescu

### Challenges and opportunities in quantum machine learning for high-energy physics

Quantum machine learning may provide powerful tools for data analysis in high-energy physics. Sau Lan Wu and Shinjae Yoo describe how the potential of these tools is starting to be tested and what has been understood thus far.

• Sau Lan Wu
•  & Shinjae Yoo
• News & Views |

### Still too small to be measured

Although the mass of the electron antineutrino is still eluding direct measurement, the KATRIN experiment with its huge spectrometer has pushed the sensitivity below a billionth of the proton mass.

• Angelo Nucciotti
Nature Physics 18, 128-129
• Research Highlights |

### Searches for magnetic monopoles

Two recent studies look for magnetic monopoles in very different, and rather exotic, places: in heavy ion collisions at the Large Hadron Collider and the IceCube neutrino detector in Antarctica.

• Iulia Georgescu