Not much new in CERN news. The latest article is a complaint about traffic jams affecting staff travel.

There’s a short article about the Higgs. Does it include physics beyond the standard model and what would be needed to find out.

There’s talk about equipment for the future amped up LHC, the “high-luminosity LHC”. https://home.cern/news/news/accelerators/hl-lhc-magnet-endurance-test-further-confirms-niobium-tins-resilience-0

HL-LHC magnet endurance test confirms niobium–tin’s resilience.

Future accelerator projects, including the high-luminosity upgrade of the Large Hadron Collider, will rely on niobium–tin (Nb3Sn) alloys for their superconducting components, such as electromagnets. The higher superconducting abilities of this material will be key in increasing the performances of our discovery machines, but stringent tests are necessary to demonstrate the resilience of niobium–tin components, as the alloy is known to be more brittle than niobium–titanium, of which current LHC components are made.

Cold, warm, cold, warm, cold, warm … over the course of two years, the quadrupole endured five thermal cycles, three of which took place in the spring of this year. Each of these cycles subjects the magnets to a 300 °C excursion in temperature: down to 1.9 K – the temperature needed to unleash their superconducting abilities – when in operation and back up to room temperature, to which magnets are regularly brought for technical operations. This process is known to be demanding for magnets, whose materials expand and contract differently with the temperature change. The niobium–tin quadrupole went through five of these thermal cycles without any sign of performance degradation.

This is the first endurance test successfully carried out on an Nb3Sn 4.2-m-long magnet, and I am happy to announce that the results are further validating this technology’s resilience and sustainability. Besides establishing the magnet’s endurance, the tests revealed that it was able to maintain its operational peak field of 11.4 T up to 4.5 K, which gives the magnet a margin of operation far exceeding the requirements imposed by the collision debris heat coming from the ATLAS and CMS experiments.

https://home.cern/news/news/physics/cms-measures-rare-particle-decay-high-precision

CMS has precisely measured the rare decay of strange B mesons to muon–antimuon pairs. Its properties agree with Standard Model predictions.

There are two types of neutral B mesons: the B0 meson consists of a beauty antiquark and a down quark, while for the Bs meson the down quark is replaced by a strange quark. If there are no new particles affecting these rare decays, researchers have predicted that only one in 250 million Bs mesons will decay into a muon–antimuon pair; for the B0 meson, the process is even more rare, at only one in 10 billion.

Both the observed Bs decay rate, found to be 3.8 ± 0.4 parts in a billion, and its lifetime measurement of 1.8 ± 0.2 picoseconds (one picosecond is one trillionth of a second), are very close to the values predicted by the Standard Model. As for the B0 decay, although no evidence of it was found from these results, physicists can state with 95% statistical confidence that its decay rate is less than 1 part in 5 billion.

In recent years, a number of anomalies have been observed in other rare B meson decays, with discrepancies between the theoretical predictions and the data – indicating the potential existence of new particles. The new CMS result is much closer to theoretical predictions than these other rare decays.

https://home.cern/news/news/cern/third-run-large-hadron-collider-has-successfully-started

On 5 July 2022 the Large Hadron Collider (LHC) detectors started recording high-energy collisions at the unprecedented energy of 13.6 TeV. After over three years of upgrade and maintenance work, the LHC is now set to run for close to four years at the record energy of 13.6 trillion electronvolts (TeV).

https://home.cern/news/news/experiments/new-lhcb-velo

The pixel detector, with its millions of microscopic pixels, each measuring 55 × 55 micrometres, can recreate particles’ trajectories at an unprecedented speed of 40 million times per second and is located only 3 millimetres from the LHCb collision point. This frenetic rate will make it possible to obtain a complete picture of the collisions in the LHC. Weighing 800 kilograms, the VELO was installed by the LHCb team with the utmost care.

https://home.cern/news/news/physics/atlas-and-cms-release-results-most-comprehensive-studies-yet-higgs-bosons

Today, exactly ten years after announcing the discovery of the Higgs boson, the international ATLAS and CMS collaborations at the Large Hadron Collider (LHC) report the results of their most comprehensive studies yet of the properties of this unique particle. The independent studies, described in two papers published today in Nature, show that the particle’s properties are remarkably consistent with those of the Higgs boson predicted by the Standard Model of particle physics.

Over 10 000 trillion proton–proton collisions and about 8 million Higgs bosons – 30 times more than at the time of the particle’s discovery. The new studies each combine an unprecedented number and variety of Higgs boson production and decay processes to obtain the most precise and detailed set of measurements to date of their rates, as well as of the strengths of the Higgs boson’s interactions with other particles. All of the measurements are remarkably consistent with the Standard Model predictions. For the Higgs boson’s interaction strength with the carriers of the weak force, an uncertainty of only 6% is achieved.

That takes us back to https://home.cern/news/news/physics/lhcb-discovers-three-new-exotic-particles and we’ve had a thread about that before. A pentaquark and two new tetraquarks.

It’s probably worth my while to look up what is expected from the 3rd LHC run. And the timeline and specifications for the amped up HL-LHC.

mollwollfumble said:

Not much new in CERN news. The latest article is a complaint about traffic jams affecting staff travel.

There’s a short article about the Higgs. Does it include physics beyond the standard model and what would be needed to find out.

There’s talk about equipment for the future amped up LHC, the “high-luminosity LHC”. https://home.cern/news/news/accelerators/hl-lhc-magnet-endurance-test-further-confirms-niobium-tins-resilience-0

HL-LHC magnet endurance test confirms niobium–tin’s resilience.

Future accelerator projects, including the high-luminosity upgrade of the Large Hadron Collider, will rely on niobium–tin (Nb3Sn) alloys for their superconducting components, such as electromagnets. The higher superconducting abilities of this material will be key in increasing the performances of our discovery machines, but stringent tests are necessary to demonstrate the resilience of niobium–tin components, as the alloy is known to be more brittle than niobium–titanium, of which current LHC components are made.

Cold, warm, cold, warm, cold, warm … over the course of two years, the quadrupole endured five thermal cycles, three of which took place in the spring of this year. Each of these cycles subjects the magnets to a 300 °C excursion in temperature: down to 1.9 K – the temperature needed to unleash their superconducting abilities – when in operation and back up to room temperature, to which magnets are regularly brought for technical operations. This process is known to be demanding for magnets, whose materials expand and contract differently with the temperature change. The niobium–tin quadrupole went through five of these thermal cycles without any sign of performance degradation.

This is the first endurance test successfully carried out on an Nb3Sn 4.2-m-long magnet, and I am happy to announce that the results are further validating this technology’s resilience and sustainability. Besides establishing the magnet’s endurance, the tests revealed that it was able to maintain its operational peak field of 11.4 T up to 4.5 K, which gives the magnet a margin of operation far exceeding the requirements imposed by the collision debris heat coming from the ATLAS and CMS experiments.

https://home.cern/news/news/physics/cms-measures-rare-particle-decay-high-precision

CMS has precisely measured the rare decay of strange B mesons to muon–antimuon pairs. Its properties agree with Standard Model predictions.

There are two types of neutral B mesons: the B0 meson consists of a beauty antiquark and a down quark, while for the Bs meson the down quark is replaced by a strange quark. If there are no new particles affecting these rare decays, researchers have predicted that only one in 250 million Bs mesons will decay into a muon–antimuon pair; for the B0 meson, the process is even more rare, at only one in 10 billion.

Both the observed Bs decay rate, found to be 3.8 ± 0.4 parts in a billion, and its lifetime measurement of 1.8 ± 0.2 picoseconds (one picosecond is one trillionth of a second), are very close to the values predicted by the Standard Model. As for the B0 decay, although no evidence of it was found from these results, physicists can state with 95% statistical confidence that its decay rate is less than 1 part in 5 billion.

In recent years, a number of anomalies have been observed in other rare B meson decays, with discrepancies between the theoretical predictions and the data – indicating the potential existence of new particles. The new CMS result is much closer to theoretical predictions than these other rare decays.

https://home.cern/news/news/cern/third-run-large-hadron-collider-has-successfully-started

On 5 July 2022 the Large Hadron Collider (LHC) detectors started recording high-energy collisions at the unprecedented energy of 13.6 TeV. After over three years of upgrade and maintenance work, the LHC is now set to run for close to four years at the record energy of 13.6 trillion electronvolts (TeV).

https://home.cern/news/news/experiments/new-lhcb-velo

The pixel detector, with its millions of microscopic pixels, each measuring 55 × 55 micrometres, can recreate particles’ trajectories at an unprecedented speed of 40 million times per second and is located only 3 millimetres from the LHCb collision point. This frenetic rate will make it possible to obtain a complete picture of the collisions in the LHC. Weighing 800 kilograms, the VELO was installed by the LHCb team with the utmost care.

https://home.cern/news/news/physics/atlas-and-cms-release-results-most-comprehensive-studies-yet-higgs-bosons

Today, exactly ten years after announcing the discovery of the Higgs boson, the international ATLAS and CMS collaborations at the Large Hadron Collider (LHC) report the results of their most comprehensive studies yet of the properties of this unique particle. The independent studies, described in two papers published today in Nature, show that the particle’s properties are remarkably consistent with those of the Higgs boson predicted by the Standard Model of particle physics.

Over 10 000 trillion proton–proton collisions and about 8 million Higgs bosons – 30 times more than at the time of the particle’s discovery. The new studies each combine an unprecedented number and variety of Higgs boson production and decay processes to obtain the most precise and detailed set of measurements to date of their rates, as well as of the strengths of the Higgs boson’s interactions with other particles. All of the measurements are remarkably consistent with the Standard Model predictions. For the Higgs boson’s interaction strength with the carriers of the weak force, an uncertainty of only 6% is achieved.

That takes us back to https://home.cern/news/news/physics/lhcb-discovers-three-new-exotic-particles and we’ve had a thread about that before. A pentaquark and two new tetraquarks.

It’s probably worth my while to look up what is expected from the 3rd LHC run. And the timeline and specifications for the amped up HL-LHC.

The 3rd run. https://www.symmetrymagazine.org/article/whats-new-for-lhc-run-3

The LHC has been shut down since 2018, but that doesn’t mean scientists have been on break. Physicists, engineers and technicians have been upgrading both the accelerator and the detectors to make the next run of the LHC—scheduled to last until the end of 2025.

Perhaps the biggest change is that CERN’s accelerator complex will no longer be fed protons, but negatively charged hydrogen ions, each made up of a proton and two electrons. As the ions are injected, the electrons will be stripped off, leaving just the protons. These protons will be joined by more negatively charged hydrogen ions, which will undergo the same process. By repeatedly interweaving negative and positive ions, scientists can create tightly packed bunches of protons. A more compact proton beam will mean more particle collisions per second.

(Comment by mollwollfumble. That’s really clever.)

Scientists are especially excited about two new features: The first is a 4.5% increase in energy—from 13 TeV to 13.6 TeV. The second is a 50% increase in the collision rate combined with luminosity leveling, a process in which the crossing angles and size of the beam are continually adjusted to maintain a steady stream of collisions for around 10 to 15 hours.

A major renovation was the replacement of ALICE’s time-projection chamber. (ALICE is used for collisions of lead nuclei rather than just proton collisions). A time-projection chamber is a gas-filled particle detector that uses electric and magnetic fields to affect the path of particles. Judging by how the particles move, scientists can then reconstruct their trajectory, momenta and properties. The new ALICE TPC, which is based on nine years’ worth of R&D, is projected to accumulate 50 times more heavy-ion collision data in the upcoming LHC Run 3 than in Runs 1 and 2 combined.

ALICE scientists also designed, built and installed a new inner tracking system, a detector that sits close to the point where particles collide. ALICE’s inner tracking system is made from silicon wafers, the same type of sensor material used to make digital cameras. The new detector will significantly increase the resolution of the “pictures” ALICE takes of particle collisions. It has a surface area of 10 square meters, making it the largest pixel detector ever built.

A major renovation at ATLAS during the long shutdown was the replacement of its two Small Wheels. The Small Wheels are detectors designed to catch muons. Even though “small” is part of their name, each wheel is 9 meters in diameter. Each wheel holds 16 wedge-shaped detector slices with 16 detecting layers each.

During the long shutdown, CMS scientists refurbished the pixel tracker, which sits a mere 2.9 centimeters away from the beam pipe, where particles circulate and collide. Around 600 million particles pass through 1 square centimeter of this inner detector every second. The CMS experiment also completed the installation of their newly designed Gas Electron Multiplier detectors, which will detect muons close to the beam pipe.

The LHCb experiment specializes in studying the properties of composite particles containing bottom quarks (hence the “b” in the name of the experiment). Scientists installed a new detector called SciFi, made from 10,000 kilometers of an optical fiber that emits light when a particle interacts with it. They also installed a new and faster Vertex Locator (VELO), a detector that will sit as close as possible to where the particles collide. What makes the new VELO detector unique is that scientists can lift it out of the way as they prepare the particle beams for collisions, then move it mechanically into place when LHCb is ready to collect data. This will allow scientists to capture clear information from the first particles that radiate from the collisions without unnecessary wear and tear from the beam.

(PS. Some LOVELY photos on that linked website. Worth looking at just for that.)

A “small wheel”.

The new linear accelerator