'We are looking for some systematic preference for the direction of these daughter protons aligned with the angular momentum we measure in the Beam-Beam Counters,' Upsal said. Because the proton comes out nearly aligned with the hyperon's spin direction, tracking where these 'daughter' protons strike the detector can be a stand-in for tracking how the hyperons' spins are aligned. 'We're specifically looking for signs of Lambda hyperons, spinning particles that decay into a proton and a pion that we measure in the Time Projection Chamber,' said Ernst Sichtermann, a deputy STAR spokesperson and senior scientist at DOE's Lawrence Berkeley National Laboratory. Meanwhile, STAR's Time Project Chamber, a gas-filled chamber that surrounds the collision zone, tracks the paths of hundreds or even thousands of particles that come out perpendicular to the center of the collisions. The size and direction of the deflection tells the physicists how much angular momentum there is and which way it is pointing for each collision event. The first, known as the Beam-Beam Counters, sit at the front and rear ends of the house-size STAR detector, catching subtle deflections in the paths of colliding particles as they pass by one another. To track the spinning particles and the angular momentum, STAR physicists correlated simultaneous measurements at two different detector components. Tracking particle spins reveals that the quark-gluon plasma created at the Relativistic Heavy Ion Collider is more swirly than the cores of super-cell tornados, Jupiter's Great Red Spot, or any other fluid! Credit: Brookhaven National Laboratory And, while there can be many small whirlpools within the QGP all pointing in random directions, on average their spins should align with what's known as the angular momentum of the system - a rotation of the system generated by the colliding particles as they speed past one another at nearly the speed of light. 'The theory is that if I have a fluid with vorticity - a whirling substructure - it tends to align the spins of the particles it emits in the same direction as the whirls,' Lisa said. Does it thermalize, or reach equilibrium, quickly enough to form vortices in the fluid itself? And if so, how does the fluid respond to the extreme vorticity?' The new analysis, which was led by Lisa and OSU graduate student Isaac Upsal, gives STAR a way to get at those finer details. 'But we want to understand this fluid at a much finer level. 'Up until now, the big story in characterizing the QGP is that it's a hot fluid that expands explosively and flows easily,' said Michael Lisa, a physicist from Ohio State University (OSU) and a member of RHIC's STAR collaboration. And with more data, it may give them a way to measure the strength of the plasma's magnetic field - an essential variable for exploring other interesting physics phenomena. Specifically, the results on vorticity, or swirling fluid motion, will help scientists sort among different theoretical descriptions of the plasma. This soup made of matter's fundamental building blocks - quarks and gluons - has a temperature hundreds of thousands of times hotter than the center of the sun and an ultralow viscosity, or resistance to flow, leading physicists to describe it as 'nearly perfect.' By studying these properties and the factors that control them, scientists hope to unlock the secrets of the strongest and most poorly understood force in nature - the one responsible for binding quarks and gluons into the protons and neutrons that form most of the visible matter in the universe today. The results, just published in Nature, add a new record to the list of remarkable properties ascribed to the quark-gluon plasma. Department of Energy Office of Science User Facility for nuclear physics research at Brookhaven National Laboratory - shows that the 'vorticity' of the QGP surpasses the whirling fluid dynamics of super-cell tornado cores and Jupiter's Great Red Spot by many orders of magnitude, and even beats out the fastest spin record held by nanodroplets of superfluid helium. The new analysis of data from the Relativistic Heavy Ion Collider (RHIC) - a U.S.

Particle collisions recreating the quark-gluon plasma (QGP) that filled the early universe reveal that droplets of this primordial soup swirl far faster than any other fluid. Because the proton comes out nearly aligned with the hyperon's spin direction, tracking where these 'daughter' protons strike the detector can be a stand-in for tracking how the hyperons' spins are aligned. Telltale signs of a lambda hyperon (Λ) decaying into a proton (p) and a pion (π-) as tracked by the Time Projection Chamber of the STAR detector.

Fun physics phenomena