The device hopes to answer the ultimate existential questions

The device hopes to answer the ultimate existential questions

The Vertex Locator at the University of Liverpool. Credit: McCoy Wynn, University of Liverpool

The final piece of an all-new detector has completed the first stage of its journey toward unlocking some of the universe’s most enduring mysteries.

The 41 million pixel Vertex Locator (VELO) was assembled at the University of Liverpool. It was assembled from components made at various institutes, before moving home to experience the beauty of the Large Hadron Collider (LHCb) at CERN.

Once installed in time to take the data, it will try to answer the following questions:

  • Why is the universe made of matter and not antimatter?
  • Why does it even exist?
  • What else is there?

A delicate balance at the dawn of space and time

In the moments immediately following the Big Bang, the universe got stuck in a delicate equilibrium between matter and antimatter.

Based on what we understand about the laws of nature, these forms of matter must have annihilated each other and left behind a universe filled with only light. However, against all odds, matter somehow gained an advantage and left something to form the universe we know today.

Our better understanding of Big Bang physics tells us that matter and antimatter originated in equal amounts. When they made contact in the early universe (which is much smaller and denser), all their combined mass was supposed to turn into pure energy. Why, and how, matter survived confrontation is one of the most profound mysteries of modern science.

The current theory is that although matter and antimatter were formed as nearly perfect mirror images, there must have been some misalignment, or small impurities. This means that some of them were not perfect reflections. Perhaps this difference, however insignificant, was enough to give the material an advantage.

Through the glass

Scientists have already found a tiny crack in the mirror called a charge parity violation (CP). This means that in some cases, the symmetry of matter and the reflection of antimatter are broken.

This results in a particle that is not quite the opposite of its twin, and this “broken symmetry” may mean that one particle can have an advantage over the other.

When this symmetry is broken, a file is created antimatter particle It may decay at a different rate than its counterpart in matter. If enough of these violations occurred after the Big Bang, that might explain why the matter remains.

By behaving differently from their antimatter counterparts, it is possible for matter particles with broken symmetry to take a little longer to decay. If this causes the material to stay a little longer, it could explain how the last person standing was.

The deep unknown

Why matter survived isn’t the only mystery in the universe. There is another issue that baffles scientists: what could happen dark matter He is?

Dark matter is a type of elusive and invisible material that supplies the gravitational glue to keep stars moving around galaxies. Because we do not yet know what dark matter is, it is possible that there is another substance, new particles And the forces in the universe that we haven’t seen yet.

Discovering anything new can reveal a radically different picture of nature than the one we have. New particles like these can announce themselves by subtly changing the way the particles we can see behave, leaving small but detectable traces in our data.

The beauty and charm of VELO

The new VELO detector, which will replace the old VELO detector, will be used to investigate subtle differences between matter and antiparticle versions of subatomic particles. These are known as beauty quarks and charm quarks.

These exotic quark-containing particles, also known as B and D mesons, are produced during collisions at the Large Hadron Collider (LHC). They are difficult to study because mesons are very unstable and fade out of existence within a split second.

When it decomposes, it actually turns into something else. Scientists believe that by studying these various aberrations and their properties, the VELO data will help the LHCb reveal the fundamental forces and symmetries of nature.

Incredibly accurate measurements

The new VELO detector will sit as close as possible to where the particles collide in the LHCb experiment. These particles decay in less than a millionth of a millionth of a second and travel only a few millimeters. So, this Close to It will give the device the best possible opportunity to measure its properties.

VELO’s sensitivity and proximity to the LHC’s beams will allow it to capture incredibly accurate measurements of particles as they decompose.

By comparing these readings to predictions made by the Standard Model (the guiding theory of particle physics) scientists can look for anomalies that might indicate new particles in nature. They can also look for CP violations or other reasons why matter and antimatter behave differently.

These deviations can revolutionize our understanding of why the universe is the way it is.

Building on the legacy of the ancient

VELO may be new and advanced but will build on the legacy of the previous VELO detector. VELO has a state-of-the-art pixel detector consisting of grids of small silicon squares that provide high accuracy even in the challenging radiation environment near LHC beams.

Its predecessor, with its lines of stacked silicon detectors, helped the LHCb make discoveries, including:

  • New states of matter.
  • Incredibly rare beauty quark decomposes.
  • Differences between Theme And Antimatter The magic of quarks.
  • The first intriguing indicator of unexplained behavior is in beauty quark decay.

Glimpses of particle behavior

UK VELO project leader Professor Themis Pocock, from the University of Liverpool, said: ‘Data captured by the old VELO detector has given us really tantalizing glimpses into particle behaviour. To make progress, we need to turn this into a really comprehensive model, Forensic investigations This is where the new VELO detector comes in. It gives us the exact set of eyes we need to observe particles at the level of detail we need. Quite simply, VELO makes the entire physics program possible on the LHCb. “

Unprecedented details

The new VELO will be able to capture these deviations in unprecedented detail.

Pair this with upgraded software and ultra-fast reading electronics that will allow beauty and magic quarks to be identified in real time. Scientists will have a device that will allow them to track and analyze the decay that was previously very difficult to reconstruct.

What else makes the new VELO Detector Unique is that scientists can lift it out of the way as they prepare the beams of particles for impact. Then, they can mechanically move it into place when the LHCb is ready for data collection.

This allows scientists to capture clear information from the first particles that radiate from the collisions without unnecessary erosion from the beam.


Subatomic particles were seen changing into antiparticles and back


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