The W mass determination at the Tevatron CDF experiment reported a deviation from the SM expectation at the 7σlevel.We discuss a few possible interpretations and their collider implications.We perform electroweak glo...The W mass determination at the Tevatron CDF experiment reported a deviation from the SM expectation at the 7σlevel.We discuss a few possible interpretations and their collider implications.We perform electroweak global fits under various frameworks and assumptions.We consider three types of electroweak global fits in the effective-field-theory framework:the S-T,S-T-δG_(F),and eight-parameter flavor-universal one.We discuss the amounts of tensions between different m_(W)measurements reflected in these fits and the corresponding shifts in central values of these parameters.With these electroweak fit pictures in hand,we present a few different classes of models and discuss their compatibility with these results.We find that while explaining the m_(W)discrepancy,the single gauge boson extensions face strong LHC direct search constraints unless the Z′is fermiophobic(leptophobic),which can be realized if extra vector fermions(leptons)mix with the SM fermions(leptons).Vector-like top partners can partially generate the needed shift to the electroweak observables.The compatibility with the top squark is also studied in detail.We find that the non-degenerate top squark soft masses enhance the needed operator coefficients,enabling an allowed explanation compatible with current LHC measurements.Overall,more theoretical and experimental developments are highly in demand to reveal the physics behind this discrepancy.展开更多
A semiring is an algebraic structure similar to a ring, but without the requirement that each element must have an additive inverse. A bounded semiring is a semiring equipped with a compatible bounded partial order. I...A semiring is an algebraic structure similar to a ring, but without the requirement that each element must have an additive inverse. A bounded semiring is a semiring equipped with a compatible bounded partial order. In this paper, properties of zero divisors and prime elements of a bounded semiring are studied. In particular, it is proved that under some mild assumption, the set Z（A） of nonzero zero divisors of A is A ／ {0, 1}, and each prime element of A is a maximal element. For a bounded semiring A with Z（A） = A ／ {0, 1}, it is proved that A has finitely many maximal elements if ACC holds either for elements of A or for principal annihilating ideals of A. As an application of prime elements, we show that the structure of a bounded semiring A is completely determined by the structure of integral bounded semirings if either ｜Z（A）｜ = 1 or ｜Z（A）｜ -- 2 and Z（A）2 ≠ 0. Applications to the ideal structure of commutative rings are also considered. In particular, when R has a finite number of ideals, it is shown that the chain complex of the poset I（R） is pure and shellable, where I（R） consists of all ideals of R.展开更多
基金supported by the National Natural Science Foundation of China (NNSFC)(12035008)supported in part by the U.S. Department of Energy (DOE)(DE-SC0022345)+7 种基金supported by"Study in Israel"Fellowship for Outstanding Post-Doctoral Researchers from ChinaPBC of CHE from Indiapartially supported by grants from the NSF-BSF (2018683)the ISF (482/20)the Azrieli foundationsupported by the NSFC (12025507, 12150015, 12047503)the Strategic Priority Research Program and Key Research Program of Frontier Science of the Chinese Academy of Sciences (XDB21010200, XDB23010000, ZDBSLY-7003)CAS project for Young Scientists in Basic Research (YSBR-006)
文摘The W mass determination at the Tevatron CDF experiment reported a deviation from the SM expectation at the 7σlevel.We discuss a few possible interpretations and their collider implications.We perform electroweak global fits under various frameworks and assumptions.We consider three types of electroweak global fits in the effective-field-theory framework:the S-T,S-T-δG_(F),and eight-parameter flavor-universal one.We discuss the amounts of tensions between different m_(W)measurements reflected in these fits and the corresponding shifts in central values of these parameters.With these electroweak fit pictures in hand,we present a few different classes of models and discuss their compatibility with these results.We find that while explaining the m_(W)discrepancy,the single gauge boson extensions face strong LHC direct search constraints unless the Z′is fermiophobic(leptophobic),which can be realized if extra vector fermions(leptons)mix with the SM fermions(leptons).Vector-like top partners can partially generate the needed shift to the electroweak observables.The compatibility with the top squark is also studied in detail.We find that the non-degenerate top squark soft masses enhance the needed operator coefficients,enabling an allowed explanation compatible with current LHC measurements.Overall,more theoretical and experimental developments are highly in demand to reveal the physics behind this discrepancy.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Grant No. 11271250）.
文摘A semiring is an algebraic structure similar to a ring, but without the requirement that each element must have an additive inverse. A bounded semiring is a semiring equipped with a compatible bounded partial order. In this paper, properties of zero divisors and prime elements of a bounded semiring are studied. In particular, it is proved that under some mild assumption, the set Z（A） of nonzero zero divisors of A is A ／ {0, 1}, and each prime element of A is a maximal element. For a bounded semiring A with Z（A） = A ／ {0, 1}, it is proved that A has finitely many maximal elements if ACC holds either for elements of A or for principal annihilating ideals of A. As an application of prime elements, we show that the structure of a bounded semiring A is completely determined by the structure of integral bounded semirings if either ｜Z（A）｜ = 1 or ｜Z（A）｜ -- 2 and Z（A）2 ≠ 0. Applications to the ideal structure of commutative rings are also considered. In particular, when R has a finite number of ideals, it is shown that the chain complex of the poset I（R） is pure and shellable, where I（R） consists of all ideals of R.
