While Large Language Models (LLMs) excel in general domains, their reliability often falls short in scientific problem-solving. The advancement of scientific AI depends on large-scale, high-quality corpora. However, existing scientific question-answering (QA) datasets suffer from high error rates, frequently resulting from logical leaps and implicit reasoning within the answers. To address this issue, we introduce LOCA (Logical Chain Augmentation), a novel framework for automatically cleaning scientific corpora, implemented through an augment-and-review loop. At its core, LOCA enhances raw answers by completing missing logical steps and explicitly separating the underlying scientific principle from its subsequent derivation. By applying LOCA to challenging scientific corpora, we demonstrate that it can automatically filter noisy datasets, typically reducing the error rate from as high as 20\% to below 2\%. LOCA provides a scalable and effective methodology for creating high-quality scientific corpora, paving the way for more reliable training and evaluation of scientific AI.

Olympiad-level physics problem-solving significantly challenges both humans and artificial intelligence (AI), as it requires integrating appropriate modeling, application of physical principles, and precise calculation within long reasoning processes. In this paper, we introduce LOCA (LOgical Chain Augmentation), an AI agent framework designed for complex physics reasoning. LOCA decomposes long reasoning into serialized atomic and verifiable steps, refining the solution through an augment-review loop. We evaluate LOCA on the 2025 Chinese Physics Olympiad (CPhO) theory examination, a rigorous testbed renowned for its depth and complexity. The framework achieves a near-perfect score of 313 out of 320 points, significantly surpassing the top human competitor and other baseline methods. Furthermore, LOCA attains a near-perfect score of 28.6 out of 30 on the IPhO 2025 examination, demonstrating its strong generalizability across different contexts. Our work points toward the development of trustworthy AI partners in both research and education.

Recently LHCb experimental group find an exotic state $T^+_{cc}$ from the process $p\bar{p} \to D^0D^0\pi^+ + X$. A key question is if it is just a molecule or may have confined tetraquark ingredient. To investigate this, different methods are taken, including two channel ($D^{*+}D^0$ and $D^{*0}D^+$) K-matrix unitarization and single channel Flatt\'e-like parametrization method analysed by pole counting rule and spectral density function sum rule. It demonstrates that $T^+_{cc}$ is a molecular state, though the possibility that there may exist elementary ingredient can not be excluded, by rough analysis on its production rate.

We study the mass spectra of hidden-charm tetraquark systems with quantum numbers (IG)JP = (1+)1+ (and their I = 1/2 partners) using QCD sum rules. The analysis incorporates the complete next-to-leading order (NLO) contribution to the perturbative QCD part of the operator product expansions, with particular attention to operator mixing effects due to renormalization group evolution. We find that both the parametric dependence and the perturbative convergence are significantly improved for the two mixed operators J_1,5^Mixed and J_2,6^Mixed , compared with those for the unmixed meson-meson or diquark-antidiquark type ones. For the dccu system, the masses of J_1,5^Mixed and J_2,6^Mixed are determined to be 3.89_-0.12^+0.18 GeV and 4.03_-0.07^+0.06 GeV, respectively, closely matching those of Zc(3900) and Zc(4020). Similarly, for the sccu states, the masses of J_1,5^Mixed and J_2,6^Mixed are found to be 4.02_-0.09^+0.17 GeV and 4.21_-0.07^+0.08 GeV, respectively, in close proximity to Zcs(3985)/Zcs(4000) and Zcs(4220), consistent with the expectation that they are the partners of Zc(3900) and Zc(4020). Our results highlight the crucial role of operator mixing, an inevitable effect in a complete NLO calculation, in achieving a robust phenomenological description for the tetraquark system.

It was found that, using nonrelativistic QCD factorization, the predicted chi(cJ) hadroproduction cross section at large p(T) can be negative. The negative cross sections originate from terms proportional to plus function in 3P(J)([1]) channels, which are remnants of the infrared subtraction in matching the 3P(J)([1]) short-distance coefficients. In this article, we find that the above terms can be factorized into the nonperturbative 3S(1)([8]) soft gluon distribution function in the soft gluon factorization (SGF) framework. Therefore, the problem can be naturally resolved in SGF. With an appropriate choice of nonperturbative parameters, the SGF can indeed give positive predictions for chi(cJ) production rates within the whole p(T) region. The production of psi(2S) is also discussed, and there is no negative cross section problem.

We study the mass spectra of hidden-charm tetraquark systems with quantum numbers (I^G)J^P=(1^+)1^+ using QCD sum rules. The analysis incorporates the complete next-to-leading order (NLO) contribution to the perturbative QCD part of the operator product expansions, with particular attention to operator mixing effects due to renormalization group evolution. For the d̅cc̅u system, the masses of two mixed operators, J_1,5^Mixed and J_2,6^Mixed, are determined to be 3.89^+0.18_-0.12 GeV and 4.03^+0.06_-0.07 GeV, respectively, closely matching those of Z_c(3900) and Z_c(4020). Similarly, for the s̅cc̅u states, the masses of J_1,5^Mixed and J_2,6^Mixed are found to be 4.02^+0.17_-0.09 GeV and 4.21^+0.08_-0.07 GeV, respectively, in close proximity to Z_cs(3983)/Z_cs(4000) and Z_cs(4220), consistent with the expectation that they are the partners of Z_c(3900) and Z_c(4020). Our results highlight the crucial role of operator mixing, an inevitable effect in a complete NLO calculation, in achieving a robust phenomenological description for the tetraquark system.

A near-threshold enhancement in the D^+_sD^-_s system, dubbed as X(3960), is observed by the LHCb collaboration recently. A combined analysis on χ _c0(3930) (→ D^+ D^-) , X(3960) (→ D^+_sD^-_s) , and X(3915) (→ J/ψω ) is performed using both a K-matrix approach of D_(s)D̅_(s) four-point contact interactions and a model of Flatté-like parameterizations. The use of the pole counting rule and spectral density function sum rule indicate, under current statistics, that this D^+_sD^-_s near-threshold state has probably the mixed nature of a cc̅ confining state and D^+_sD^-_s continuum.

A bstract We have studied color-octet contributions for J/ψ inclusive production at B factories, i.e., e + e − → J/ψ ( 3 $$ {P}_J^{\left[8\right]} $$ P J 8 , 1 $$ {S}_0^{\left[8\right]} $$ S 0 8 ) + $$ {X}_{\mathrm{non}-c\overline{c}} $$ X non − c c ¯ , using the soft gluon factorization (SGF) approach, in which the J/ψ energy spectrum is expressed in a form of perturbatively calculable short-distance hard parts convoluted with one-dimensional soft gluon distributions (SGDs). The series of velocity corrections originated from kinematic effect can be naturally resummed in this approach. Short-distance hard parts have been calculated analytically to next-to-leading order in α s . Renormalization group equations for SGDs have been derived and solved, which resums Sudakov logarithms originated from soft gluon emissions. Our final result gives a upper bound for color-octet matrix elements consistent with that extracted from hadron colliders. This may relieve the well-known universality problem in the NRQCD factorization. As a comparison, we also analytically calculated short-distance hard parts in the NRQCD factorization, with Sudakov logarithms resummed by using soft collinear effective theory. The comparison shows that velocity corrections from kinematic effect, which have been resummed in SGF, are significant for phenomenological study. Furthermore, it is found that Sudakov logarithms originated from soft gluon emissions are very important, while it is not the case for Sudakov logarithms originated from jet function. Therefore, the partial Sudakov resummation in SGF has already captured the main physics.

A bstract We study the mass spectra of $$ \overline{Q}Q\overline{Q}Q $$ Q ¯ Q Q ¯ Q ( Q = c, b ) systems in QCD sum rules with the complete next-to-leading order (NLO) contribution to the perturbative QCD part of the correlation functions. Instead of meson-meson or diquark-antidiquark currents, we use diagonalized currents under operator renormalization. We find that differing from conventional mesons $$ \overline{q}q $$ q ¯ q and baryons qqq , a unique feature of the multiquark systems like $$ \overline{Q}Q\overline{Q}Q $$ Q ¯ Q Q ¯ Q is the operator mixing or color configuration mixing induced by NLO corrections, which is crucial to understand the color structure of the states. Our numerical results show that the NLO corrections are very important for the $$ \overline{Q}Q\overline{Q}Q $$ Q ¯ Q Q ¯ Q system, because they not only give significant contributions but also reduce the scheme and scale dependence and make Borel platform more distinct, especially for the $$ \overline{b}b\overline{b}b $$ b ¯ b b ¯ b in the $$ \overline{\textrm{MS}} $$ MS ¯ scheme. We use currents that have good perturbation convergence in our phenomenological analysis. With the $$ \overline{\textrm{MS}} $$ MS ¯ scheme, we get three J PC = 0 ++ states, with masses $$ {6.35}_{-0.17}^{+0.20} $$ 6.35 − 0.17 + 0.20 GeV, $$ {6.56}_{-0.20}^{+0.18} $$ 6.56 − 0.20 + 0.18 GeV and $$ {6.95}_{-0.35}^{+0.21} $$ 6.95 − 0.35 + 0.21 GeV, respectively. The first two seem to agree with the broad structure around 6 . 2 ~ 6 . 8 GeV measured by the LHCb collaboration in the J/ψJ/ψ spectrum, and the third seems to agree with the narrow resonance X (6900). For the 2 ++ states we find one with mass $$ {7.03}_{-0.26}^{+0.22} $$ 7.03 − 0.26 + 0.22 GeV, which is also close to that of X (6900), and another one around $$ {7.25}_{-0.35}^{+0.21} $$ 7.25 − 0.35 + 0.21 GeV, which has good scale dependence but slightly large scheme dependence.

AbstractThe next-to-leading order (NLO) ($$ \mathcal{O} $$O($$ {\alpha}_s^3 $$αs3)) corrections for gluon fragmentation functions to a heavy quark-antiquark pair in3$$ {P}_J^{\left[1,8\right]} $$PJ18states are calculated within the NRQCD factorization. We use the integration-by-parts reduction and differential equations to semi-analytically calculate the fragmentation functions in full-QCD, and find that infrared divergences can be absorbed by the NRQCD long distance matrix elements. Thus, the NRQCD factorization conjecture is verified at two-loop level via a physical process, which is free of artificial ultraviolet divergences. Through the matching procedure, infrared-safe short distance coefficients and$$ \mathcal{O} $$O($$ {\alpha}_s^2 $$αs2) perturbative NRQCD matrix elements ⟨$$ {\mathcal{O}}^3{P}_J^{\left[1,8\right]} $$O3PJ18(3$$ {S}_1^{\left[8\right]} $$S18)⟩ are obtained simultaneously. The NLO short distance coefficients are found to have significant corrections comparing with the LO ones.

We study the triply heavy baryons Omega(QQQ) (Q = c,b) in the QCD Sum Rules by calculating the next-to-leading order (NLO) contribution in the perturbative QCD part of the correlation functions. Compared with the leading order (LO) result, the NLO contribution is found to be very important to the Omega(QQQ). This is because the NLO not only results in a large correction, but also reduces the parameters dependence and makes the Borel platform more distinct, especially for the Omega(QQQ) in the (MS) over bar scheme, where the platform appears only at NLO but not at LO. In particular, due to the inclusion of the NLO contribution, the renormalization schemes ((MS) over bar and On-Shell) dependence and scale dependence are significantly improved. As a result, after including the NLO contribution of the perturbative part in QCD sum rules, the masses are predicted to be 4.53(-0.11)(+0.26) GeV for Omega(ccc) and 14.27(-0.32)(+0.33) GeV for Omega(bbb), where the results are obtained at mu=M-B with errors including that from the variation of the renormalization scale mu in the range (0.8-1.2)M-B. A careful study for the mu dependence in a wider range is further performed, which shows that the LO results are very sensitive to the choice of mu whereas the NLO results are much better. In addition to the mu=M-B result, a quite stable value, (4.75-4.80) GeV, for the Omega(ccc) mass is found in the range of mu=(1.2-2.0)M-B.

bstract We study the fragmentation function of the gluon to color-octet 3 S 1 heavy quark-antiquark pair using the soft gluon factorization (SGF) approach, which expresses the fragmentation function in a form of perturbative short-distance hard part convoluted with one-dimensional color-octet 3 S 1 soft gluon distribution (SGD). The short distance hard part is calculated to the next-to-leading order in α s and all orders in velocity expansion. By deriving and solving the renormalization group equation of the SGD, threshold logarithms are resummed to all orders in perturbation theory. The comparison with gluon fragmentation function calculated in NRQCD factorization approach indicates that the SGF formula resums a series of velocity corrections in NRQCD which are important for phenomenological study.

Abstract We study the fragmentation function of the gluon to color-octet 3 S 1 heavy quark-antiquark pair using the soft gluon factorization (SGF) approach, which expresses the fragmentation function in a form of perturbative short-distance hard part convoluted with one-dimensional color-octet 3 S 1 soft gluon distribution (SGD). The short distance hard part is calculated to the next-to-leading order in α s and all orders in velocity expansion. By deriving and solving the renormalization group equation of the SGD, threshold logarithms are resummed to all orders in perturbation theory. The comparison with gluon fragmentation function calculated in NRQCD factorization approach indicates that the SGF formula resums a series of velocity corrections in NRQCD which are important for phenomenological study.

With the QCD sum rules approach, we study the newly discovered doubly heavy baryon Xi(++)(cc). We analytically calculate the next-to-leading-order (NLO) contribution to the perturbative part of the J(P) = 1/2(+) baryon current with two identical heavy quarks, and then reanalyze the mass of Xi(++)(cc) at the NLO level. We find that the NLO correction significantly improves both scheme dependence and scale dependence, whereas it is hard to control these theoretical uncertainties at leading order. With the NLO contribution, the baryon mass is estimated to be m(Xi cc++) = 3.66(-0.10)(+0.08) GeV, which is consistent with the LHCb measurement.

We calculate the NLO corrections for the gluon fragmentation functions to a heavy quark-antiquark pair in 1S 0 [1] or 1S 0 [8] state within NRQCD factorization. We use integration-by-parts reduction to reduce the original expression to simpler master integrals (MIs), and then set up differential equations for these MIs. After calculating the boundary conditions, MIs can be obtained by solving the differential equations numerically. Our results are expressed in terms of asymptotic expansions at singular points of z (light-cone momentum fraction carried by the quark-antiquark pair), which can not only give FFs results with very high precision at any value of z, but also provide fully analytical structure at these singularities. We find that the NLO corrections are significant, with K-factors larger than 2 in most regions. The NLO corrections may have important impact on heavy quarkonia (e.g. ηc and J/ψ) production at the LHC.

We calculate the NLO corrections for the gluon fragmentation functions to a heavy quarkantiquark pair in S [1] 0 or S [8] 0 state within NRQCD factorization. We use integration-by-parts reduction to reduce the original expression to simpler master integrals (MIs), and then set up differential equations for these MIs. After calculating the boundary conditions, MIs can be obtained by solving the differential equations numerically. Our results are expressed in terms of asymptotic expansions at singular points of z (light-cone momentum fraction carried by the quark-antiquark pair), which can not only give FFs results with very high precision at any value of z, but also provide fully analytical structure at these singularities. We find that the NLO corrections are significant, with K-factors larger than 2 in most regions. The NLO corrections may have important impact on heavy quarkonia (e.g. ηc and J/ψ) production at the LHC.

Hao Han, Yan-Qing Ma, Ce Meng, Hua-Sheng Shao, Yu-Jie Zhang, Kuang-Ta Chao (a) School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China (b) Maryland Center for Fundamental Physics, University of Maryland, College Park, Maryland 20742, USA (c) Center for High Energy physics, Peking University, Beijing 100871, China (d) Key Laboratory of Micro-nano Measurement-Manipulation and Physics (Ministry of Education) and School of Physics, Beihang University, Beijing 100191, China (e)Collaborative Innovation Center of Quantum Matter, Beijing 100871, China

We evaluate the production cross sections of X(3872) at the LHC and Tevatron at NLO in alpha(s) in NRQCD by assuming that the short-distance production proceeds dominantly through chi'(c1) component in our chi'(c1) - D-0(D) over bar*(0) mixing model for X(3872). The outcomes of the fits to the CMS p(T) distribution can well account for the recent ATLAS data in a much larger range of transverse momenta (10 GeV < p(T) < 70 GeV) and the CDF total cross section data, and are also consistent with the value of k = Z(c (c) over bar) . Br(X -> J/Psi pi(+)pi(-)) constrained by the B-meson decay data. For LHCb, the predicted X(3872) total cross section is larger than the data by a factor of 2, which is due to the problem of the fixed-order NRQCD calculation that may not be applicable for the region with small p(T) (p(T) similar to 5 GeV) and large forward rapidity (2.5 < y < 4.5). In comparison, the prediction of the molecule production mechanism for X(3872) is inconsistent with both p(T) distributions and total cross sections of CMS and ATLAS, and the total cross section of CDF.

A comprehensive study on the nature of the Z_c(3900) resonant structure is carried out in this work. By constructing the pertinent effective Lagrangians and considering the important final-state-interaction effects, we first give a unified description to all the relevant experimental data available, including the J/ψπ and ππ invariant mass distributions from the e^+e^-→ J/ψππ process, the h_cπ distribution from e^+e^-→ h_cππ and also the DD̅^* spectrum in the e^+e^-→ DD̅^*π process. After fitting the unknown parameters to the previous data, we search the pole in the complex energy plane and find only one pole in the nearby energy region in different Riemann sheets. Therefore we conclude that Z_c(3900) is of DD̅^* molecular nature, according to the pole counting rule method [Nucl. Phys. A543, 632 (1992); Phys. Rev. D 35, 1633 (1987)]. We emphasize that the conclusion based upon the pole counting method is not trivial, since both the DD̅^* contact interactions and the explicit Z_c exchanges are introduced in our analyses and they lead to the same conclusion.