The Quest for Millicharged Particles
A deep dive into the search for elusive millicharged particles in particle physics.
J. Aalbers, D. S. Akerib, A. K. Al Musalhi, F. Alder, C. S. Amarasinghe, A. Ames, T. J. Anderson, N. Angelides, H. M. Araújo, J. E. Armstrong, M. Arthurs, A. Baker, S. Balashov, J. Bang, J. W. Bargemann, E. E. Barillier, D. Bauer, K. Beattie, T. Benson, A. Bhatti, A. Biekert, T. P. Biesiadzinski, H. J. Birch, E. Bishop, G. M. Blockinger, B. Boxer, C. A. J. Brew, P. Brás, S. Burdin, M. Buuck, M. C. Carmona-Benitez, M. Carter, A. Chawla, H. Chen, J. J. Cherwinka, Y. T. Chin, N. I. Chott, M. V. Converse, R. Coronel, A. Cottle, G. Cox, D. Curran, C. E. Dahl, I. Darlington, S. Dave, A. David, J. Delgaudio, S. Dey, L. de Viveiros, L. Di Felice, C. Ding, J. E. Y. Dobson, E. Druszkiewicz, S. Dubey, S. R. Eriksen, A. Fan, S. Fayer, N. M. Fearon, N. Fieldhouse, S. Fiorucci, H. Flaecher, E. D. Fraser, T. M. A. Fruth, R. J. Gaitskell, A. Geffre, J. Genovesi, C. Ghag, A. Ghosh, R. Gibbons, S. Gokhale, J. Green, M. G. D. van der Grinten, J. J. Haiston, C. R. Hall, T. J. Hall, S. Han, E. Hartigan-O'Connor, S. J. Haselschwardt, M. A. Hernandez, S. A. Hertel, G. Heuermann, G. J. Homenides, M. Horn, D. Q. Huang, D. Hunt, E. Jacquet, R. S. James, J. Johnson, A. C. Kaboth, A. C. Kamaha, Meghna K. K., D. Khaitan, A. Khazov, I. Khurana, J. Kim, Y. D. Kim, J. Kingston, R. Kirk, D. Kodroff, L. Korley, E. V. Korolkova, H. Kraus, S. Kravitz, L. Kreczko, V. A. Kudryavtsev, C. Lawes, D. S. Leonard, K. T. Lesko, C. Levy, J. Lin, A. Lindote, W. H. Lippincott, M. I. Lopes, W. Lorenzon, C. Lu, S. Luitz, P. A. Majewski, A. Manalaysay, R. L. Mannino, C. Maupin, M. E. McCarthy, G. McDowell, D. N. McKinsey, J. McLaughlin, J. B. McLaughlin, R. McMonigle, E. Mizrachi, A. Monte, M. E. Monzani, J. D. Morales Mendoza, E. Morrison, B. J. Mount, M. Murdy, A. St. J. Murphy, A. Naylor, H. N. Nelson, F. Neves, A. Nguyen, C. L. O'Brien, I. Olcina, K. C. Oliver-Mallory, J. Orpwood, K. Y Oyulmaz, K. J. Palladino, J. Palmer, N. J. Pannifer, N. Parveen, S. J. Patton, B. Penning, G. Pereira, E. Perry, T. Pershing, A. Piepke, Y. Qie, J. Reichenbacher, C. A. Rhyne, A. Richards, Q. Riffard, G. R. C. Rischbieter, E. Ritchey, H. S. Riyat, R. Rosero, T. Rushton, D. Rynders, D. Santone, A. B. M. R. Sazzad, R. W. Schnee, G. Sehr, B. Shafer, S. Shaw, T. Shutt, J. J. Silk, C. Silva, G. Sinev, J. Siniscalco, R. Smith, V. N. Solovov, P. Sorensen, J. Soria, I. Stancu, A. Stevens, K. Stifter, B. Suerfu, T. J. Sumner, M. Szydagis, D. R. Tiedt, M. Timalsina, Z. Tong, D. R. Tovey, J. Tranter, M. Trask, M. Tripathi, A. Usón, A. Vacheret, A. C. Vaitkus, O. Valentino, V. Velan, A. Wang, J. J. Wang, Y. Wang, J. R. Watson, L. Weeldreyer, T. J. Whitis, K. Wild, M. Williams, W. J. Wisniewski, L. Wolf, F. L. H. Wolfs, S. Woodford, D. Woodward, C. J. Wright, Q. Xia, J. Xu, Y. Xu, M. Yeh, D. Yeum, W. Zha, E. A. Zweig
― 7 min read
Table of Contents
- What Are Millicharged Particles?
- The LUX-ZEPLIN Experiment
- Cosmic Rays and Atmospheric Interactions
- Searching for mCPs
- Theoretical Importance of mCPs
- Models of Interaction
- The Experimental Setup
- Challenges in Detection
- Background Noise
- Results and Findings
- Future Directions
- Conclusion
- Original Source
- Reference Links
The search for Millicharged Particles (mCPs) is a fascinating topic in the realm of particle physics. To put it simply, mCPs are theoretical particles that carry a tiny fraction of the charge of an electron. Think of them like tiny "electric mice" that have just a tiny bit of electrical charge. Researchers are eager to find these elusive particles since they could provide clues about the universe's secrets.
What Are Millicharged Particles?
Millicharged particles are not your everyday particles. Compared to regular particles, they have a considerably smaller electric charge, which is why they can be so hard to find. These particles could arise from various theoretical frameworks, including string theory and grand unification theories. They might also interact with dark matter, which is a type of matter that doesn’t emit light and is not directly observable. In layman's terms, if normal particles are like well-known celebrities, mCPs are like a celebrity who has only appeared in a couple of social media posts.
The LUX-ZEPLIN Experiment
One of the main efforts to find mCPs took place at the LUX-ZEPLIN (LZ) experiment. Located 4850 feet underground, this facility is like a secret lair for scientists trying to solve the mysteries of the universe. The LZ experiment uses a dual-phase xenon time projection chamber, which is a fancy way of saying it has a setup that can detect tiny energy signals produced by interactions between particles. The team behind this experiment recently embarked on a quest to find mCPs produced from Cosmic Rays—those energetic particles flying through space and hitting the Earth’s atmosphere.
Cosmic Rays and Atmospheric Interactions
Cosmic rays are like the universe's way of keeping things exciting. When they collide with atoms in our atmosphere, they create a cascade of secondary particles. Some of these interactions can produce mCPs through two known processes: Meson Decay and proton bremsstrahlung.
- Meson Decay: This is when mesons, a type of particle, turn into other particles, including mCPs.
- Proton Bremsstrahlung: In this scenario, a cosmic ray proton crashes into an atom and produces mCPs through the emission of photons.
You could say these processes are akin to cosmic rays throwing a wild party in the atmosphere, where sometimes mCPs get invited!
Searching for mCPs
During its first science run, the LZ experiment recorded data for about 60 days, hoping to find signs of mCPs. The researchers adopted a unique approach, utilizing the properties of liquid xenon (LXe) to enhance their search efforts.
Imagine trying to spot a tiny needle in a giant haystack. That’s what searching for mCPs feels like. The search required very sensitive equipment to catch even the faintest signs of these lightweight particles. Unfortunately, the researchers didn’t find any significant excess of mCPs over the expected Background Noise, which is like hearing crickets when you wanted to hear a rock band.
Theoretical Importance of mCPs
Even though the search didn’t yield immediate results, the quest for millicharged particles is important. The existence of mCPs could challenge our current understanding of particle physics and shed light on dark matter's nature. Scientists propose that mCPs could account for a small fraction of dark matter, which is exciting because dark matter is one of the biggest mysteries in the universe. If these little particles exist, it would be like finding a missing puzzle piece that makes the picture clearer.
Models of Interaction
To understand how mCPs might behave, researchers consider different interaction models. These models describe how mCPs would react when they encounter other particles in the detector.
- Free Electron Model: This model assumes that all electrons in LXe are free to move. It's like a party where everyone is dancing freely without any worries.
- Photon Absorption Ionization (PAI) Model: This model considers that some electrons are bound to atoms and have to work harder to participate in the dance. It’s like a party where some guests are stuck in the corner and need a little encouragement to join in.
By running simulations with these two models, researchers can better determine what kind of signals they might expect from mCP interactions. This is critical in figuring out if they have spotted an mCP or if it’s just the background noise playing tricks on them.
The Experimental Setup
The LZ experiment's equipment is impressive. The setup consists of a large cylindrical chamber filled with liquid xenon, surrounded by layers of additional protective materials.
The chamber captures the signals from particle interactions, creating two distinct types of signals that scientists analyze: scintillation light and ionization electrons. The complex dance of these signals helps researchers figure out where and when a particle interaction occurred.
Additionally, the LZ team uses various detectors to ensure the signals are genuine and not just random noise. It’s the equivalent of having guards at the party to ensure no uninvited guests crash the festivities.
Challenges in Detection
Finding mCPs isn’t easy. The energy deposited by mCPs during interactions is often very small, which makes it challenging to detect them. To detect these minuscule deposits, researchers need to be quick on their feet. They must distinguish between actual mCP signals and background noise effectively.
Researchers also have to consider that as mCPs travel through the Earth’s layers, they lose energy. So, by the time they reach the detectors, they might not have enough energy left to generate a detectable signal. This is akin to guests at a party getting tired and leaving before having a good time.
Background Noise
The LZ experiment also contends with background noise, which can mimic the signals expected from mCPs. Two main types of background signals can confuse researchers:
- Single Scatter Events: Events where a true signal overlaps with random smaller signals caused by the environment.
- Multiple Scattering Events: Background signals from the activity of the detector itself, like ghosts haunting a party.
To tackle these pesky mimics, researchers developed rigorous selection criteria to screen out likely false signals and focus on genuine interactions. This careful filtering is necessary to ensure that the search for mCPs is as accurate as possible.
Results and Findings
After all the hard work and the implementation of various techniques, the LZ team concluded that they had not detected any mCPs during their first science run. This result aligns with the expectations based on the background models. Despite the lack of exciting discoveries, the team’s efforts contributed to the broader understanding of potential mCPs and set constraints on their existence.
Researchers also gathered valuable information that will assist future experimental designs aimed at detecting mCPs. Their work acts like a building block in particle physics, paving the way for future studies and advances in the field.
Future Directions
While the search for mCPs in this particular run was unsuccessful, the LZ team remains optimistic. Future runs will build on the knowledge gained from this experience and incorporate improved techniques and methods.
The quest for mCPs is ongoing, and researchers will continue to explore various production channels and models. As technology advances, there may be a breakthrough that helps them catch these elusive particles. Until then, the scientific community will keep the lights on at the particle physics party, hoping for a surprise guest to show up.
Conclusion
The hunt for millicharged particles represents a thrilling chapter in particle physics. Though the LZ experiment did not find mCPs in its first run, the knowledge gained and the constraints set provide a solid foundation for future searches. The journey of discovery continues, and researchers remain dedicated to unraveling the mysteries of the universe, even if those mysteries come with a small charge!
Original Source
Title: First search for atmospheric millicharged particles with the LUX-ZEPLIN experiment
Abstract: We report on a search for millicharged particles (mCPs) produced in cosmic ray proton atmospheric interactions using data collected during the first science run of the LUX-ZEPLIN experiment. The mCPs produced by two processes -- meson decay and proton bremsstrahlung -- are considered in this study. This search utilized a novel signature unique to liquid xenon (LXe) time projection chambers (TPCs), allowing sensitivity to mCPs with masses ranging from 10 to 1000 MeV/c$^2$ and fractional charges between 0.001 and 0.02 of the electron charge e. With an exposure of 60 live days and a 5.5 tonne fiducial mass, we observed no significant excess over background. This represents the first experimental search for atmospheric mCPs and the first search for mCPs using an underground LXe experiment.
Authors: J. Aalbers, D. S. Akerib, A. K. Al Musalhi, F. Alder, C. S. Amarasinghe, A. Ames, T. J. Anderson, N. Angelides, H. M. Araújo, J. E. Armstrong, M. Arthurs, A. Baker, S. Balashov, J. Bang, J. W. Bargemann, E. E. Barillier, D. Bauer, K. Beattie, T. Benson, A. Bhatti, A. Biekert, T. P. Biesiadzinski, H. J. Birch, E. Bishop, G. M. Blockinger, B. Boxer, C. A. J. Brew, P. Brás, S. Burdin, M. Buuck, M. C. Carmona-Benitez, M. Carter, A. Chawla, H. Chen, J. J. Cherwinka, Y. T. Chin, N. I. Chott, M. V. Converse, R. Coronel, A. Cottle, G. Cox, D. Curran, C. E. Dahl, I. Darlington, S. Dave, A. David, J. Delgaudio, S. Dey, L. de Viveiros, L. Di Felice, C. Ding, J. E. Y. Dobson, E. Druszkiewicz, S. Dubey, S. R. Eriksen, A. Fan, S. Fayer, N. M. Fearon, N. Fieldhouse, S. Fiorucci, H. Flaecher, E. D. Fraser, T. M. A. Fruth, R. J. Gaitskell, A. Geffre, J. Genovesi, C. Ghag, A. Ghosh, R. Gibbons, S. Gokhale, J. Green, M. G. D. van der Grinten, J. J. Haiston, C. R. Hall, T. J. Hall, S. Han, E. Hartigan-O'Connor, S. J. Haselschwardt, M. A. Hernandez, S. A. Hertel, G. Heuermann, G. J. Homenides, M. Horn, D. Q. Huang, D. Hunt, E. Jacquet, R. S. James, J. Johnson, A. C. Kaboth, A. C. Kamaha, Meghna K. K., D. Khaitan, A. Khazov, I. Khurana, J. Kim, Y. D. Kim, J. Kingston, R. Kirk, D. Kodroff, L. Korley, E. V. Korolkova, H. Kraus, S. Kravitz, L. Kreczko, V. A. Kudryavtsev, C. Lawes, D. S. Leonard, K. T. Lesko, C. Levy, J. Lin, A. Lindote, W. H. Lippincott, M. I. Lopes, W. Lorenzon, C. Lu, S. Luitz, P. A. Majewski, A. Manalaysay, R. L. Mannino, C. Maupin, M. E. McCarthy, G. McDowell, D. N. McKinsey, J. McLaughlin, J. B. McLaughlin, R. McMonigle, E. Mizrachi, A. Monte, M. E. Monzani, J. D. Morales Mendoza, E. Morrison, B. J. Mount, M. Murdy, A. St. J. Murphy, A. Naylor, H. N. Nelson, F. Neves, A. Nguyen, C. L. O'Brien, I. Olcina, K. C. Oliver-Mallory, J. Orpwood, K. Y Oyulmaz, K. J. Palladino, J. Palmer, N. J. Pannifer, N. Parveen, S. J. Patton, B. Penning, G. Pereira, E. Perry, T. Pershing, A. Piepke, Y. Qie, J. Reichenbacher, C. A. Rhyne, A. Richards, Q. Riffard, G. R. C. Rischbieter, E. Ritchey, H. S. Riyat, R. Rosero, T. Rushton, D. Rynders, D. Santone, A. B. M. R. Sazzad, R. W. Schnee, G. Sehr, B. Shafer, S. Shaw, T. Shutt, J. J. Silk, C. Silva, G. Sinev, J. Siniscalco, R. Smith, V. N. Solovov, P. Sorensen, J. Soria, I. Stancu, A. Stevens, K. Stifter, B. Suerfu, T. J. Sumner, M. Szydagis, D. R. Tiedt, M. Timalsina, Z. Tong, D. R. Tovey, J. Tranter, M. Trask, M. Tripathi, A. Usón, A. Vacheret, A. C. Vaitkus, O. Valentino, V. Velan, A. Wang, J. J. Wang, Y. Wang, J. R. Watson, L. Weeldreyer, T. J. Whitis, K. Wild, M. Williams, W. J. Wisniewski, L. Wolf, F. L. H. Wolfs, S. Woodford, D. Woodward, C. J. Wright, Q. Xia, J. Xu, Y. Xu, M. Yeh, D. Yeum, W. Zha, E. A. Zweig
Last Update: 2024-12-10 00:00:00
Language: English
Source URL: https://arxiv.org/abs/2412.04854
Source PDF: https://arxiv.org/pdf/2412.04854
Licence: https://creativecommons.org/licenses/by/4.0/
Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.
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