Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

STAR Heavy Flavor Tracker Detects Signs of Charm at RHIC

20.04.2015

New detector component picks up particles composed of heavy quarks to probe primordial quark-gluon plasma.

The Science


Image courtesy of Brookhaven National Laboratory

The Heavy Flavor Tracker being installed in the heart of the STAR detector at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory.

Thousands of times a second the Relativistic Heavy Ion Collider (RHIC), a particle collider at Brookhaven National Laboratory, creates a quark-gluon plasma—a recreation of the hot quark soup that existed at the dawn of the universe. Particles composed of heavy quarks—which go by whimsical names such as “charm” and “beauty”—can help reveal subtle details about the quark-gluon plasma, and by extension, the early universe and the origins of matter.

The Impact

Nuclear physicists conducting research at RHIC now have the ability to detect these rare, elusive particles using the Heavy Flavor Tracker (HFT), a new component recently installed as part of the STAR experiment. This device will help to precisely measure the plasma’s properties, including its ability to flow like a nearly perfect liquid, and can offer insight into how certain particles lose energy as they traverse the plasma.

Summary

Particles composed of quarks that are heavier than the “up” and “down” quarks that make up ordinary atomic nuclei can help reveal subtle details about a primordial soup made of matter’s building blocks—known as a quark-gluon plasma. This hot quark soup, which existed at the dawn of the universe, is recreated thousands of times a second when ordinary nuclei are smashed together in energetic collisions at the Relativistic Heavy Ion Collider (RHIC), a particle collider at Brookhaven National Laboratory. But the particles containing heavy quarks—which go by whimsical names such as “charm” and “beauty”—are produced only rarely and disappear in an instant. Nuclear physicists conducting research at RHIC now have the ability to detect these rare, elusive particles using the Heavy Flavor Tracker (HFT), a new component recently installed as part of the STAR experiment. This device will help to precisely measure the plasma’s properties, including its ability to flow like a nearly perfect liquid, and can offer insight into how certain particles lose energy as they traverse the plasma.

The STAR Heavy Flavor Tracker (HFT) will provide precise measurements of the production rates of particles containing different combinations of heavy quarks, some of which are heavier than others. Measuring how the heavy particles interact with the quark-gluon plasma will give physicists further insight into the plasma's ability to flow with extremely low viscosity, or resistance—almost like dropping variously sized pebbles into a stream to see how fast it is flowing. These measurements may also help explain the mechanism by which even high-momentum particles appear to lose energy to the plasma. The different abundances and masses of heavy quarks can help differentiate how matter interacts with quarks and provide insight into thermalization—how the matter created in RHIC’s collisions approaches thermal equilibrium. These measurements will lead to a better understanding of properties of the quark-gluon plasma and will stimulate new theoretical studies.

The energy deposited when RHIC collides gold ions at nearly the speed of light creates thousands of new particles, including some rare combinations of different types of heavy quarks. These heavy particles decay in the time it takes them to travel about 100 microns—about the width of a hair. The HFT, now inserted within the core of the STAR experiment, was designed to identify these fleeting heavy particles using a four-layer silicon detector. The first two layers are state-of-the-art pixel detectors (PXL) in which each layer uses silicon pixels with dimensions of 20 by 20 micrometers mounted on very light structures. The PXL detector is the first at a collider to use a new detector concept called Monolithic Active Pixel Sensors (MAPS). The MAPS sensors are thinned to 50 micrometers and have been placed very close to the beam line in which the particle collisions take place so they can track the elusive heavy particles immediately after they decay. The entire PXL detector can be retracted and if necessary replaced with a spare within a 24-hour period. Both the high resolution and the low mass of the detector represent a breakthrough in pixel technology. Two additional silicon-detector systems are used to increase the efficiency of the HFT. A single cylindrical layer of silicon pad detectors (IST) surrounds the PXL. The outermost detection layer consists of double-sided Silicon Strip Detectors (SSD).

The PXL detector was designed and built at Lawrence Berkeley National Laboratory (LBNL) using novel MAPS sensors that were developed at Institut Pluridisciplinaire Hubert CURIEN (IPHC, Strasbourg, France). The IST was designed and built at MIT, the University of Illinois at Chicago, and Indiana University; while the SSD readout electronics were built at LBNL and designed by a collaboration between LBNL and Subatech (Nantes, France). Overall detector integration was done by BNL and LBNL; and project management was provided by BNL with assistance from LBNL.

Installed at the STAR detector in time for the 2014 RHIC run, the HFT detector has so far recorded 1.2 billion gold-gold collision events, meeting all expectations in its performance to date. The STAR collaboration has begun analyzing this abundance of new data and looks forward to incorporating it into a deeper understanding of the quark-gluon plasma created at RHIC.

Funding

The Heavy Flavor Tracker is an Office of Nuclear Physics supported MIE project which was initiated in 2010. The following STAR institutions are collaborators in this work: BNL, Czech Technical University and NPI Prague, UCLA, Indiana University Cyclotron Facility, IPHC Strasbourg, MIT, LBNL, Purdue University, SUBATECH Nantes, UIC and UT Austin.

Publications

L. Greiner et al., "A MAPS based vertex detector for the STAR experiment at RHIC." Nucl. Instr. and Meth. A 650 (1), 68-72 (2010). [DOI: 10.1016/j.nima.2010.12.006]

C. Hu-Guo et al., "First reticule size MAPS with digital output and integrated zero suppression for the EUDET-JRA1 beam telescope." Nucl. Instrum. Meth. A 623 (1), 480-482 (2010). [DOI: 10.1016/j.nima.2010.03.043]

Contact Information
Kristin Manke
kristin.manke@science.doe.gov

Kristin Manke | newswise
Further information:
http://www.science.doe.gov

More articles from Physics and Astronomy:

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin

nachricht Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>