One of the most challenging aspects of hadron physics is represented by the proton spin and its interpretation in terms of its internal constituents. The issue rose dramatically in the late 1980s when the European Muon Collaboration (EMC) conducted experiments suggesting that, contrary to the naive expectation, the spin carried by quarks is only a small fraction of the total spin of the proton. The problem of where the missing spin lies is referred to as the “proton spin crisis.” Although more than twenty years have passed since these first pioneering experiments, during which our theoretical and experimental knowledge have enormously deepened, the proton-spin has not yet revealed all of its mystery.
Perspectives for Polarized Antiprotons
LENISA, Paolo;
2013
Abstract
One of the most challenging aspects of hadron physics is represented by the proton spin and its interpretation in terms of its internal constituents. The issue rose dramatically in the late 1980s when the European Muon Collaboration (EMC) conducted experiments suggesting that, contrary to the naive expectation, the spin carried by quarks is only a small fraction of the total spin of the proton. The problem of where the missing spin lies is referred to as the “proton spin crisis.” Although more than twenty years have passed since these first pioneering experiments, during which our theoretical and experimental knowledge have enormously deepened, the proton-spin has not yet revealed all of its mystery.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
