Son Cao, P. T. Quyen, N. T. Hong Van, Ankur Nath, T. V. Ngoc
Among three leptonic mixing angles, $theta_{23}$ angle, which characterizes the fractional contribution of two flavor eigenstates $nu_{mu}$ and $nu_{tau}$ to the third mass eigenstate $nu_3$, is known to be the largest but the least precisely measured. The work investigates possible reach of $theta_{23}$ precision with two upcoming gigantic accelerator-based long-baseline neutrino experiments, namely Hyper-Kamiokande and DUNE experiments as well as a possible joint analyses of future neutrino facilities. Our simulation yields that each experiment will definitely establish the octant of $theta_{23}$ angle for all values within 1$sigma$ parameter interval, while considering the current limitation. However, if the actual value is $0.48leq sin^2theta_{23}leq 0.54$, it becomes challenging for these two experiments to reject the maximal ($theta_{23}=pi/4$) hypothesis and conclude its octant. This octant-blind region can be further explored with the proposed facilities ESSnuSB and a neutrino factory. Accurate determination of the mixing angle $theta_{23}$, as well as the accuracy of $delta_{CP}$, is crucial for examining a certain category of discrete non-Abelian leptonic flavor models. Specifically if CP is conserved in leptonic sector, the combined analysis of Hyper-K and DUNE will rule out the majority of these models. However, if the CP is maximally violated, higher precision of $delta_{CP}$ is necessary for testing these flavor models.
{"title":"On Precision of the Leptonic Mixing Angle $θ_{23}$ and its Implications for the Flavor Models","authors":"Son Cao, P. T. Quyen, N. T. Hong Van, Ankur Nath, T. V. Ngoc","doi":"arxiv-2409.11824","DOIUrl":"https://doi.org/arxiv-2409.11824","url":null,"abstract":"Among three leptonic mixing angles, $theta_{23}$ angle, which characterizes\u0000the fractional contribution of two flavor eigenstates $nu_{mu}$ and\u0000$nu_{tau}$ to the third mass eigenstate $nu_3$, is known to be the largest\u0000but the least precisely measured. The work investigates possible reach of\u0000$theta_{23}$ precision with two upcoming gigantic accelerator-based\u0000long-baseline neutrino experiments, namely Hyper-Kamiokande and DUNE\u0000experiments as well as a possible joint analyses of future neutrino facilities.\u0000Our simulation yields that each experiment will definitely establish the octant\u0000of $theta_{23}$ angle for all values within 1$sigma$ parameter interval,\u0000while considering the current limitation. However, if the actual value is\u0000$0.48leq sin^2theta_{23}leq 0.54$, it becomes challenging for these two\u0000experiments to reject the maximal ($theta_{23}=pi/4$) hypothesis and conclude\u0000its octant. This octant-blind region can be further explored with the proposed\u0000facilities ESSnuSB and a neutrino factory. Accurate determination of the mixing\u0000angle $theta_{23}$, as well as the accuracy of $delta_{CP}$, is crucial for\u0000examining a certain category of discrete non-Abelian leptonic flavor models.\u0000Specifically if CP is conserved in leptonic sector, the combined analysis of\u0000Hyper-K and DUNE will rule out the majority of these models. However, if the CP\u0000is maximally violated, higher precision of $delta_{CP}$ is necessary for\u0000testing these flavor models.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, we revisit unweighted event generation for multi-parton tree-level processes in massless QCD. We introduce a two-step approach, in which initially unweighted events are generated at leading-colour (LC) accuracy, followed by a reweighting of these events to full-colour (FC) accuracy and applying an additional unweighting cycle. This method leverages the simple structure of LC integrands, enabling optimized phase-space parameterisations and resulting in high primary unweighting efficiencies, ranging from the percent level for $2 to 4$ processes to the per-mille level for $2 to 7$ processes. Given that the LC-accurate matrix elements closely approximate the FC-accurate ones, the secondary unweighting efficiencies exceed 50%. Our results suggest that this two-step approach offers an efficient alternative to direct event generation at FC accuracy.
在这项工作中，我们重新审视了无质量 QCD 中多部分顶层过程的非加权事件生成。我们引入了一种两步法，即首先以前导色（LC）精度生成非加权事件，然后将这些事件重新加权到全色（FC）精度，并应用额外的非加权循环。这种方法利用了 LC 积分的简单结构，实现了优化的相位-空间参数化，并产生了很高的初级去重效率，从 2 美元到 4 美元过程的百分比水平，到 2 美元到 7 美元过程的每百万分之一水平。鉴于 LC 精确矩阵元素与 FC 精确矩阵元素非常接近，二次去重效率超过了 50%。我们的结果表明，这种两步法提供了一种高效的替代方法，可以在 FC 精确度下直接生成事件。
{"title":"Leading-colour-based unweighted event generation for multi-parton tree-level processes","authors":"Rikkert Frederix, Timea Vitos","doi":"arxiv-2409.12128","DOIUrl":"https://doi.org/arxiv-2409.12128","url":null,"abstract":"In this work, we revisit unweighted event generation for multi-parton\u0000tree-level processes in massless QCD. We introduce a two-step approach, in\u0000which initially unweighted events are generated at leading-colour (LC)\u0000accuracy, followed by a reweighting of these events to full-colour (FC)\u0000accuracy and applying an additional unweighting cycle. This method leverages\u0000the simple structure of LC integrands, enabling optimized phase-space\u0000parameterisations and resulting in high primary unweighting efficiencies,\u0000ranging from the percent level for $2 to 4$ processes to the per-mille level\u0000for $2 to 7$ processes. Given that the LC-accurate matrix elements closely\u0000approximate the FC-accurate ones, the secondary unweighting efficiencies exceed\u000050%. Our results suggest that this two-step approach offers an efficient\u0000alternative to direct event generation at FC accuracy.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we take a close look at the interaction between the TeV--PeV energy astrophysical neutrinos and a hypothetical cosmic sterile-neutrino background. These interactions yield absorption features, also called ``dips", in the astrophysical neutrino spectrum, which are studied using the deposited energy distribution of high-energy starting events (HESE) in the IceCube detector. We improve upon the previous analysis by including the effects of regeneration and a realistic source distribution on the propagation of astrophysical neutrinos. We use the latest 7.5-year HESE dataset and include the observation of Glashow resonance in our analysis. We evaluate the impact of these dips on the inferred spectral index and overall normalization of the astrophysical neutrinos. We find a mild preference for dips in the 300--800 TeV range, and the best-fit parameters for the mass of sterile-neutrino and the mediator are 0.5 eV and 23 MeV, respectively. We find that the inclusion of these absorption features lowers the spectral index of astrophysical neutrinos to $2.60^{+0.19}_{-0.16}$. The lower spectral index can reduce the disagreement with the Northern Tracks sample but requires dedicated analysis. We also forecast the event spectrum for IceCube-Gen2 for the two different fits.
{"title":"Probing the cosmic sterile-neutrino background with IceCube","authors":"Bhavesh Chauhan, Priyank Parashari","doi":"arxiv-2409.12145","DOIUrl":"https://doi.org/arxiv-2409.12145","url":null,"abstract":"In this paper, we take a close look at the interaction between the TeV--PeV\u0000energy astrophysical neutrinos and a hypothetical cosmic sterile-neutrino\u0000background. These interactions yield absorption features, also called ``dips\",\u0000in the astrophysical neutrino spectrum, which are studied using the deposited\u0000energy distribution of high-energy starting events (HESE) in the IceCube\u0000detector. We improve upon the previous analysis by including the effects of\u0000regeneration and a realistic source distribution on the propagation of\u0000astrophysical neutrinos. We use the latest 7.5-year HESE dataset and include\u0000the observation of Glashow resonance in our analysis. We evaluate the impact of\u0000these dips on the inferred spectral index and overall normalization of the\u0000astrophysical neutrinos. We find a mild preference for dips in the 300--800 TeV\u0000range, and the best-fit parameters for the mass of sterile-neutrino and the\u0000mediator are 0.5 eV and 23 MeV, respectively. We find that the inclusion of\u0000these absorption features lowers the spectral index of astrophysical neutrinos\u0000to $2.60^{+0.19}_{-0.16}$. The lower spectral index can reduce the disagreement\u0000with the Northern Tracks sample but requires dedicated analysis. We also\u0000forecast the event spectrum for IceCube-Gen2 for the two different fits.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the present work, we have studied the masses and magnetic moments of spin$-{frac{1}{2}}^+$ and spin$-{frac{3}{2}}^+$ singly and doubly charmed baryons in the strange hadronic medium at finite temperature using the chiral SU(3) quark mean field model. The properties of baryons within the framework of chiral SU(3) mean field model are defined in terms of constituent quark masses and energies, which are modified through the exchange of scalar fields $sigma$, $zeta$ and $delta$ and the vector fields $omega$, $rho$ and $phi$. The scalar-isovector field, $delta$ and the vector-isovector field, $rho$ contribute when medium has finite isospin asymmetry. We have calculated the effective masses of constituent quarks and charmed baryons in the nuclear and strange matter within the chiral SU(3) quark mean field model and have used these as the input in SU(4) constituent chiral quark model to compute the effective magnetic moments of these baryons. Considering the configuration mixing, the contributions of valence quarks, quark sea and orbital angular momentum of quark sea have been considered explicitly to calculate the in-medium magnetic moments.
{"title":"Effective masses and magnetic moments of charmed baryons in asymmetric hot strange hadronic matter","authors":"Suneel Dutt, Arvind Kumar, Harleen Dahiya","doi":"arxiv-2409.11878","DOIUrl":"https://doi.org/arxiv-2409.11878","url":null,"abstract":"In the present work, we have studied the masses and magnetic moments of\u0000spin$-{frac{1}{2}}^+$ and spin$-{frac{3}{2}}^+$ singly and doubly charmed\u0000baryons in the strange hadronic medium at finite temperature using the chiral\u0000SU(3) quark mean field model. The properties of baryons within the framework of\u0000chiral SU(3) mean field model are defined in terms of constituent quark masses\u0000and energies, which are modified through the exchange of scalar fields\u0000$sigma$, $zeta$ and $delta$ and the vector fields $omega$, $rho$ and\u0000$phi$. The scalar-isovector field, $delta$ and the vector-isovector field,\u0000$rho$ contribute when medium has finite isospin asymmetry. We have calculated\u0000the effective masses of constituent quarks and charmed baryons in the nuclear\u0000and strange matter within the chiral SU(3) quark mean field model and have used\u0000these as the input in SU(4) constituent chiral quark model to compute the\u0000effective magnetic moments of these baryons. Considering the configuration\u0000mixing, the contributions of valence quarks, quark sea and orbital angular\u0000momentum of quark sea have been considered explicitly to calculate the\u0000in-medium magnetic moments.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigated the electromagnetic quadrupole transition of baryon decuplet ($J^P= frac{3}{2}^+$) to octet ($J^P= frac{1}{2}^+$) using the statistical framework together with the principle of detailed balance. The statistical approach assumed the expansion of hadrons in terms of various quark-gluon Fock states. By specifying the appropriate multiplicity in spin, color $&$ flavor space, the relative probabilities of strange and non-strange quark-gluon Fock state are calculated. These probabilities further accumulated in the form of statistical parameters, highlighting the importance of sea quarks and gluons in the electromagnetic transition. Our calculations includes the individual contribution of valence and sea (scalar, vector and tensor ) to the transition moment of baryons. The effect of flavor SU(3) symmetry and its breaking in both valence and sea quarks is studied by incorporating the strange quark mass. The strangeness in the sea is constrained by a suppression factor $(1-C_l)^{n-1}$, which depends upon the free energy of gluons. The computed results get affected upto 60 $%$ and exhibit the dominance of octet sea. The present work has been compared with updated experimental data and various theoretical predictions. The results obtained may offer important insights for future experimental studies.
{"title":"Sea-quark dynamics in decuplet ($frac{3}{2}^+$) $rightarrow$ octet ($frac{1}{2}^+$) transition quadrupole moment","authors":"Preeti Bhall, Alka Upadhyay","doi":"arxiv-2409.11740","DOIUrl":"https://doi.org/arxiv-2409.11740","url":null,"abstract":"We investigated the electromagnetic quadrupole transition of baryon decuplet\u0000($J^P= frac{3}{2}^+$) to octet ($J^P= frac{1}{2}^+$) using the statistical\u0000framework together with the principle of detailed balance. The statistical\u0000approach assumed the expansion of hadrons in terms of various quark-gluon Fock\u0000states. By specifying the appropriate multiplicity in spin, color $&$ flavor\u0000space, the relative probabilities of strange and non-strange quark-gluon Fock\u0000state are calculated. These probabilities further accumulated in the form of\u0000statistical parameters, highlighting the importance of sea quarks and gluons in\u0000the electromagnetic transition. Our calculations includes the individual\u0000contribution of valence and sea (scalar, vector and tensor ) to the transition\u0000moment of baryons. The effect of flavor SU(3) symmetry and its breaking in both\u0000valence and sea quarks is studied by incorporating the strange quark mass. The\u0000strangeness in the sea is constrained by a suppression factor $(1-C_l)^{n-1}$,\u0000which depends upon the free energy of gluons. The computed results get affected\u0000upto 60 $%$ and exhibit the dominance of octet sea. The present work has been\u0000compared with updated experimental data and various theoretical predictions.\u0000The results obtained may offer important insights for future experimental\u0000studies.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study the Primordial Black Hole (PBH) reheating scenario, where PBHs originate in a general cosmological background. In this scenario, ultralight PBHs with masses $Mlesssim 10^8$g temporarily dominate the Universe and reheat it via Hawking radiation before Big Bang Nucleosynthesis (BBN). We investigate whether the induced Gravitational Wave (GW) spectrum associated with PBH reheating contains information about the pre-PBH-dominated stage, namely the initial equation of state $w$ (after inflation). We first derive the transfer functions of curvature fluctuations for general $w$ with adiabatic and isocurvature initial conditions. We find that, in general, a stiffer equation of state enhances the induced GW amplitude as it allows for a longer PBH dominated phase compared to the radiation dominated case. We also find that the spectral slope of GWs induced by primordial curvature fluctuations is sensitive to $w$, while the spectral slope of GWs induced by PBH number density fluctuations is not. Lastly, we derive constraints of the initial PBH abundance as a function of $w$, using BBN and Cosmic Microwave Background (CMB) observations. A stiffer equation of state leads to stricter constraints on the initial energy density fraction, as induced GWs are enhanced. Interestingly, we find that such induced GW signals may enter the observational window of several future GW detectors, such as LISA and the Einstein Telescope. Our formulas, especially the curvature fluctuation transfer functions, are applicable to any early matter-dominated universe scenario.
{"title":"From formation to evaporation: Induced gravitational wave probes of the primordial black hole reheating scenario","authors":"Guillem Domènech, Jan Tränkle","doi":"arxiv-2409.12125","DOIUrl":"https://doi.org/arxiv-2409.12125","url":null,"abstract":"We study the Primordial Black Hole (PBH) reheating scenario, where PBHs\u0000originate in a general cosmological background. In this scenario, ultralight\u0000PBHs with masses $Mlesssim 10^8$g temporarily dominate the Universe and reheat\u0000it via Hawking radiation before Big Bang Nucleosynthesis (BBN). We investigate\u0000whether the induced Gravitational Wave (GW) spectrum associated with PBH\u0000reheating contains information about the pre-PBH-dominated stage, namely the\u0000initial equation of state $w$ (after inflation). We first derive the transfer\u0000functions of curvature fluctuations for general $w$ with adiabatic and\u0000isocurvature initial conditions. We find that, in general, a stiffer equation\u0000of state enhances the induced GW amplitude as it allows for a longer PBH\u0000dominated phase compared to the radiation dominated case. We also find that the\u0000spectral slope of GWs induced by primordial curvature fluctuations is sensitive\u0000to $w$, while the spectral slope of GWs induced by PBH number density\u0000fluctuations is not. Lastly, we derive constraints of the initial PBH abundance\u0000as a function of $w$, using BBN and Cosmic Microwave Background (CMB)\u0000observations. A stiffer equation of state leads to stricter constraints on the\u0000initial energy density fraction, as induced GWs are enhanced. Interestingly, we\u0000find that such induced GW signals may enter the observational window of several\u0000future GW detectors, such as LISA and the Einstein Telescope. Our formulas,\u0000especially the curvature fluctuation transfer functions, are applicable to any\u0000early matter-dominated universe scenario.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We develop the formalism for production of a fully heavy tetraquark and apply it to the calculation of $ppto T_{4c}+X$ cross-sections. We demonstrate that the production cross-section of a fully heavy tetraquark, even if it is a diquark-antidiquark cluster, can be obtained in the meson-like basis, for which the spin-color projection technique is well established. Prompted by the recent LHCb, ATLAS and CMS data, we perform a pQCD calculation of ${cal O}(alpha_s^5)$ short-distance factors in the dominant channel of gluon fusion, and match these to the four-body $T_{4c}$ wave functions in order to obtain the unpolarized $T_{4c}(0^{++},1^{+-},2^{++})$ cross-sections. The novelty in comparison with the recently published article~cite{Feng:2023agq} lies in the fact that we predict the absolute values as well as the $dsigma/dp_T$ spectra in the kinematic ranges accessible at the ongoing LHC experiments. From the comparison with the signal yield at LHCb we derive the constraints on the $Phicdottext{Br}(J/psi,J/psi)$ (reduced wave function times branching) product for the $T_{4c}$ candidates for $X(6900)$ and observe that $X(6900)$ is compatible with a $2^{++}(2S)$ state.
{"title":"Fully charmed tetraquark production at the LHC experiments","authors":"Ilia Belov, Alessandro Giachino, Elena Santopinto","doi":"arxiv-2409.12070","DOIUrl":"https://doi.org/arxiv-2409.12070","url":null,"abstract":"We develop the formalism for production of a fully heavy tetraquark and apply\u0000it to the calculation of $ppto T_{4c}+X$ cross-sections. We demonstrate that\u0000the production cross-section of a fully heavy tetraquark, even if it is a\u0000diquark-antidiquark cluster, can be obtained in the meson-like basis, for which\u0000the spin-color projection technique is well established. Prompted by the recent\u0000LHCb, ATLAS and CMS data, we perform a pQCD calculation of ${cal\u0000O}(alpha_s^5)$ short-distance factors in the dominant channel of gluon fusion,\u0000and match these to the four-body $T_{4c}$ wave functions in order to obtain the\u0000unpolarized $T_{4c}(0^{++},1^{+-},2^{++})$ cross-sections. The novelty in\u0000comparison with the recently published article~cite{Feng:2023agq} lies in the\u0000fact that we predict the absolute values as well as the $dsigma/dp_T$ spectra\u0000in the kinematic ranges accessible at the ongoing LHC experiments. From the\u0000comparison with the signal yield at LHCb we derive the constraints on the\u0000$Phicdottext{Br}(J/psi,J/psi)$ (reduced wave function times branching)\u0000product for the $T_{4c}$ candidates for $X(6900)$ and observe that $X(6900)$ is\u0000compatible with a $2^{++}(2S)$ state.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ubiquity of top-rich final states in the context of beyond the Standard Model (BSM) searches has led to their status as extensively studied signatures at the LHC. Over the past decade, numerous endeavours have been undertaken in the literature to develop methods for efficiently distinguishing boosted top quark jets from QCD jets. Although cut-based strategies for boosted top tagging, which rely on substructure information from fat jets resulting from the hadronic decay of boosted top quarks, were introduced in the literature as early as 2008, recent years have witnessed a surge in the utilization of machine learning-based approaches for the classification of top-jets from QCD jets. The review focuses on the present status of boosted top tagging and its application for BSM searchers.
{"title":"Unveiling the Secrets of New Physics Through Top Quark Tagging","authors":"Rameswar Sahu, Saiyad Ashanujjaman, Kirtiman Ghosh","doi":"arxiv-2409.12085","DOIUrl":"https://doi.org/arxiv-2409.12085","url":null,"abstract":"The ubiquity of top-rich final states in the context of beyond the Standard\u0000Model (BSM) searches has led to their status as extensively studied signatures\u0000at the LHC. Over the past decade, numerous endeavours have been undertaken in\u0000the literature to develop methods for efficiently distinguishing boosted top\u0000quark jets from QCD jets. Although cut-based strategies for boosted top\u0000tagging, which rely on substructure information from fat jets resulting from\u0000the hadronic decay of boosted top quarks, were introduced in the literature as\u0000early as 2008, recent years have witnessed a surge in the utilization of\u0000machine learning-based approaches for the classification of top-jets from QCD\u0000jets. The review focuses on the present status of boosted top tagging and its\u0000application for BSM searchers.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study the weak decays of heavy mesons into baryon pairs, focusing on channels dominated by annihilation-type diagrams, where short-distance (SD) contributions are highly suppressed. We focus on decays with small energy release to further ensure the dominance of long-distance (LD) physics. The final state interactions of the triangular diagrams do not require a cutoff, making our numerical results reliable. Moreover, the hidden strangeness in the intermediate state naturally avoids chiral suppression. The branching fractions are predicted to be ${cal B}(D_s^+ to poverline{n}) = (1.43 pm 0.10 ) times 10^{-3}$ and ${cal B} (B_s^0 to Lambda_c^+ overline{Lambda}_c^-) > 4.7 times 10^{-5}$, respectively. The former is in agreement with the experimental data of $(1.22 pm 0.11)times 10^{-3}$, while the latter suggests that a measurement is now feasible. Using the experimental upper bound of ${cal B} (B_s^0 to Lambda_c^+ overline{Lambda}_c^-) < 8 times 10^{-5}$, we set a constraint on the coupling constant $g_{D^+ Lambda_c^+ n} < 7.5$. The CP symmetry suggests that $B_{sH/L}^0 to Lambda_c^+ overline{Lambda}_c^-$ is dominated by $P/S$ wave. This selection rule distinguishes the SD and LD contributions, allowing experiments to further test our understanding in the nonperturbative region. We propose future measurements on $B^0 to Xi_c^+ overline{Xi}_c^-$ to test final state interaction mechanisms, predicting significant $SU(3)_F$ breaking effects with ${cal B}(B^0 to Xi_c^+ overline{Xi}_c^-) / {cal B} (B_s^0 to Lambda_c^+ overline{Lambda}_c^-) = 1.4%$, contrary to the naive estimate of $5.3%$.
我们研究重介子成重子对的弱衰变，重点是以湮灭型图为主的通道，其中短距离（SD）贡献被高度抑制。我们关注能量释放较小的衰变，以进一步确保长距离（LD）物理的主导地位。三角形图的终态相互作用不需要截止，这使得我们的数值结果非常可靠。此外，中间态的隐藏陌生化自然避免了手性抑制。预测的分支分数分别为 ${cal B}(D_s^+ to poverline{n}) = (1.43 pm 0.10 )times 10^{-3}$ 和 ${cal B} (B_s^0 to Lambda_c^+ overline{Lambda}_c^-) >4.7 times 10^{-5}$。前者与实验数据 $(1.22 pm 0.11)times 10^{-3}$ 一致，而后者表明测量现在是可行的。利用实验上限 ${cal B} (B_s^0 to Lambda_c^+ overline{Lambda}_c^-) < 8 times 10^{-5}$，我们设定了耦合常数 $g_{D^+ Lambda_c^+ n} < 7.5 的约束。< 7.5$.CP对称性表明$B_{sH/L}^0 toLambda_c^+ overline{Lambda}_c^-$ 是由$P/S$波支配的。这一选择规则区分了SD和LD的贡献，使得实验可以进一步检验我们对当时非微扰区域的理解。我们建议未来对 $B^0 to Xi_c^+overline{Xi}_c^-$ 进行测量，以检验终态相互作用机制、预测显著的 $SU(3)_F$ 断裂效应为 ${cal B}(B^0 to Xi_c^+overline{Xi}_c^-) / {cal B} (B_s^0 to Lambda_c^+ overline{Lambda}_c^-) =1.4%$, 与天真的估计值 5.3%$ 相反。
{"title":"Hidden strangeness in meson weak decays to baryon pair","authors":"Chao-Qiang Geng, Xian-Nan Jin, Chia-Wei Liu, Xiao Yu","doi":"arxiv-2409.11374","DOIUrl":"https://doi.org/arxiv-2409.11374","url":null,"abstract":"We study the weak decays of heavy mesons into baryon pairs, focusing on\u0000channels dominated by annihilation-type diagrams, where short-distance (SD)\u0000contributions are highly suppressed. We focus on decays with small energy\u0000release to further ensure the dominance of long-distance (LD) physics. The\u0000final state interactions of the triangular diagrams do not require a cutoff,\u0000making our numerical results reliable. Moreover, the hidden strangeness in the\u0000intermediate state naturally avoids chiral suppression. The branching fractions\u0000are predicted to be ${cal B}(D_s^+ to poverline{n}) = (1.43 pm 0.10 )\u0000times 10^{-3}$ and ${cal B} (B_s^0 to Lambda_c^+ overline{Lambda}_c^-) >\u00004.7 times 10^{-5}$, respectively. The former is in agreement with the\u0000experimental data of $(1.22 pm 0.11)times 10^{-3}$, while the latter suggests\u0000that a measurement is now feasible. Using the experimental upper bound of\u0000${cal B} (B_s^0 to Lambda_c^+ overline{Lambda}_c^-) < 8 times 10^{-5}$,\u0000we set a constraint on the coupling constant $g_{D^+ Lambda_c^+ n} < 7.5$. The\u0000CP symmetry suggests that $B_{sH/L}^0 to Lambda_c^+ overline{Lambda}_c^-$\u0000is dominated by $P/S$ wave. This selection rule distinguishes the SD and LD\u0000contributions, allowing experiments to further test our understanding in the\u0000nonperturbative region. We propose future measurements on $B^0 to Xi_c^+\u0000overline{Xi}_c^-$ to test final state interaction mechanisms, predicting\u0000significant $SU(3)_F$ breaking effects with ${cal B}(B^0 to Xi_c^+\u0000overline{Xi}_c^-) / {cal B} (B_s^0 to Lambda_c^+ overline{Lambda}_c^-) =\u00001.4%$, contrary to the naive estimate of $5.3%$.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. G. Parrott, B. Colquhoun, A. Francis, R. J. Hudspith, R. Lewis, K. Maltman
The existence of bound doubly heavy tetraquark states was confirmed by the recent LHCb discovery of the doubly charmed $T_{cc}$, less than 1 MeV below the meson pair threshold. Others states with two heavy (bottom or charm) quarks could also be bound, perhaps more deeply. Here we discuss our previous work, and the improvements in our current, updated analysis of various heavy-heavy-light-light tetraquark candidates, including the light and heavy quark mass dependence of the binding.
{"title":"Quark mass dependence of doubly heavy tetraquark binding","authors":"W. G. Parrott, B. Colquhoun, A. Francis, R. J. Hudspith, R. Lewis, K. Maltman","doi":"arxiv-2409.11477","DOIUrl":"https://doi.org/arxiv-2409.11477","url":null,"abstract":"The existence of bound doubly heavy tetraquark states was confirmed by the\u0000recent LHCb discovery of the doubly charmed $T_{cc}$, less than 1 MeV below the\u0000meson pair threshold. Others states with two heavy (bottom or charm) quarks\u0000could also be bound, perhaps more deeply. Here we discuss our previous work,\u0000and the improvements in our current, updated analysis of various\u0000heavy-heavy-light-light tetraquark candidates, including the light and heavy\u0000quark mass dependence of the binding.","PeriodicalId":501067,"journal":{"name":"arXiv - PHYS - High Energy Physics - Phenomenology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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