The study investigates the chiral anomaly of multifold fermions in CoSi, a material that hosts higher-spin generalizations of Weyl quasiparticles. The chiral anomaly, a hallmark of chiral spin-1/2 Weyl fermions, is an imbalance between left- and right-moving particles, leading to phenomena such as negative longitudinal magnetoresistance. The researchers measured the magnetoresistance in CoSi and found an intrinsic, longitudinal negative magnetoresistance, which they attributed to the chiral anomaly of multifold fermions. They developed a semiclassical theory to explain the magnetotransport, considering both the Berry curvature and orbital magnetic moment contributions. The theory showed that the negative magnetoresistance originates from the chiral anomaly, despite the significant orbital magnetic moment contribution. The results confirm the chiral anomaly of higher-spin generalizations of Weyl fermions and provide a new perspective on quantum anomalies in condensed matter systems.The study investigates the chiral anomaly of multifold fermions in CoSi, a material that hosts higher-spin generalizations of Weyl quasiparticles. The chiral anomaly, a hallmark of chiral spin-1/2 Weyl fermions, is an imbalance between left- and right-moving particles, leading to phenomena such as negative longitudinal magnetoresistance. The researchers measured the magnetoresistance in CoSi and found an intrinsic, longitudinal negative magnetoresistance, which they attributed to the chiral anomaly of multifold fermions. They developed a semiclassical theory to explain the magnetotransport, considering both the Berry curvature and orbital magnetic moment contributions. The theory showed that the negative magnetoresistance originates from the chiral anomaly, despite the significant orbital magnetic moment contribution. The results confirm the chiral anomaly of higher-spin generalizations of Weyl fermions and provide a new perspective on quantum anomalies in condensed matter systems.