scholarly journals Exploring Possible Triangle Singularities in the Ξ b − → K − J / ψ Λ Decay

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1611
Author(s):  
Chao-Wei Shen ◽  
Hao-Jie Jing ◽  
Feng-Kun Guo ◽  
Jia-Jun Wu
Keyword(s):  
Invariant Mass ◽  
Invariant Mass Distribution ◽  
Physical Region ◽  
Invariant Mass Spectrum ◽  
Triangle Diagram ◽  
P Waves ◽  
Peak Structure ◽  
Quantum Numbers ◽  
Intermediate States ◽  
The One

We analyze possible singularities in the J/ψΛ invariant mass distribution of the Ξb−→K−J/ψΛ process via triangle loop diagrams. Triangle singularities in the physical region are found in 18 different triangle loop diagrams. Among those with Ξ*-charmonium-Λ intermediate states, the one from the χc1Ξ(2120)Λ loop, which is located around 4628 MeV, is found the most likely to cause observable effects. One needs S- and P-waves in χc1Λ and J/ψΛ systems, respectively, when the quantum numbers of these systems are 1/2+ or 3/2+. When the quantum numbers of the Ξ(2120) are JP=1/2+, 1/2− or 3/2+, the peak structure should be sharper than the other JP choices. This suggests that although the whole strength is unknown, we should pay attention to the contributions from the Ξ*-charmonium-Λ triangle diagram if structures are observed in the J/ψΛ invariant mass spectrum experimentally. In addition, a few triangle diagrams with the Ds1*(2700) as one of the intermediate particles can also produce singularities in the J/ψΛ distribution, but at higher energies above 4.9 GeV.

scholarly journals Role of N*(1535) in the Λ+c → K0ηp decay and the possible фp state in the Λ+c → π0фp decay

2020 ◽  
Vol 241 ◽  
pp. 02010
Author(s):  
Ju-Jun Xie ◽  
Li-Sheng Geng ◽  
Feng-Kun Guo
Keyword(s):  
Invariant Mass ◽  
Mass Distribution ◽  
Final State Interaction ◽  
Invariant Mass Distribution ◽  
Lagrangian Model ◽  
Final State ◽  
Peak Structure ◽  
Effective Lagrangian ◽  
Unitary Approach ◽  
Chiral Unitary Approach

The nonleptonic weak decays of Λ+c → K0ηp and Λ+c → π0фp are investigated from the viewpoint of probing the N*(1535) resonance and the possible фp state. For the Λ+c → K0ηp decay, we study the invariant mass distribution of ηp with both the chiral unitary approach and an effective Lagrangian model. Within the chiral unitary approach, the N*(1535) resonance is dynamically generated from the final state interaction of mesons and baryons in coupled channels. While for the effective Lagrangian model, we take a Breit-Wigner formula for the N*(1535) resonance. We found that the behavior of the N*(1535) resonance in the Λ+c → K0N*(1535) → K0ηp decay within the two approaches is different. For the Λ+c → π0фp decay, we consider a triangle singularity mechanism, where the Λ+c decays into the K*Σ*(1385), the Σ*(1385) decays into the π0Σ/Λ, and then the K*Σ/Λ merge to produce the фp in the final state. This mechanism produces a peak structure around 2020 MeV. In addition, the possibility that there is a hidden-strange pentaquark-like state is also considered by taking into account the final state interactions of K*Λ, K*Σ, and фp. We conclude that it is difficult to search for the hidden-strange state in this decay. However, we do expect nontrivial behavior in the фp invariant mass distribution. The proposed Λ+c decay mechanism here can provide valuable information on the properties of these nuclear resonances and can in principle be tested by experiments such as BESIII, LHCb and Belle-II.

scholarly journals QED corrections in $$ \overline{B}\to \overline{K}{\mathrm{\ell}}^{+}{\mathrm{\ell}}^{-} $$ at the double-differential level

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Gino Isidori ◽  
Saad Nabeebaccus ◽  
Roman Zwicky
Keyword(s):  
Phase Space ◽  
Detailed Analysis ◽  
Invariant Mass ◽  
Mass Distribution ◽  
Invariant Mass Distribution ◽  
Semileptonic Decays ◽  
Lepton Pair ◽  
Specific Choice ◽  
Slicing Method

Abstract We present a detailed analysis of QED corrections to $$ \overline{B}\to \overline{K}{\mathrm{\ell}}^{+}{\mathrm{\ell}}^{-} $$ B ¯ → K ¯ ℓ + ℓ − decays at the double-differential level. Cancellations of soft and collinear divergences are demonstrated analytically using the phase space slicing method. Whereas soft divergences are found to cancel at the differential level, the cancellation of the hard-collinear logs ln mℓ require, besides photon-inclusiveness, a specific choice of kinematic variables. In particular, hard-collinear logs in the lepton-pair invariant mass distribution (q2), are sizeable and need to be treated with care when comparing with experiment. Virtual and real amplitudes are evaluated using an effective mesonic Lagrangian. Crucially, we show that going beyond this approximation does not introduce any further infrared sensitive terms. All analytic computations are performed for generic charges and are therefore adaptable to semileptonic decays such as $$ \overline{B}\to D\mathrm{\ell}\overline{\nu } $$ B ¯ → D ℓ ν ¯ .

scholarly journals Invariant-mass distribution of top-quark pairs and top-quark mass determination

2020 ◽  
Vol 44 (9) ◽  
pp. 091001
Author(s):  
Wan-Li Ju ◽  
Guoxing Wang ◽  
Xing Wang ◽  
Xiaofeng Xu ◽  
Yongqi Xu ◽  
...  
Keyword(s):  
Invariant Mass ◽  
Mass Distribution ◽  
Top Quark ◽  
Quark Mass ◽  
Invariant Mass Distribution ◽  
Mass Determination ◽  
Top Quark Mass ◽  
Quark Pairs ◽  
Top Quark Pairs

STUDY OF THE DIJET INVARIANT MASS IN W + JETS EVENTS BY THE DØ COLLABORATION

2012 ◽  
Vol 27 (01) ◽  
pp. 1230002
Author(s):  
JADRANKA SEKARIC
Keyword(s):  
Mass Spectrum ◽  
Invariant Mass ◽  
Experimental Verification ◽  
Hadron Collider ◽  
Mass Range ◽  
Invariant Mass Spectrum ◽  
Dijet Production ◽  
Dijet Mass ◽  
Two Jets ◽  
Recent Claim

The recent claim by the CDF Collaboration of a possible anomalous dijet resonance in their data required experimental verification from other hadron collider experiments. We present a study of the dijet invariant mass spectrum in events with two jets produced in association with a W→ℓν boson at the DØ experiment. We investigate the dijet mass range between 110 GeV /c2 and 170 GeV /c2 and find no evidence for any resonant dijet production.

scholarly journals Search for a Structure in the Bs0π± Invariant Mass Spectrum with the ATLAS Experiment

2018 ◽  
Vol 120 (20) ◽  
Author(s):  
M. Aaboud ◽  
G. Aad ◽  
B. Abbott ◽  
O. Abdinov ◽  
B. Abeloos ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Invariant Mass ◽  
Invariant Mass Spectrum ◽  
Atlas Experiment

Contribution ofπ0and η Dalitz decays to the dilepton invariant-mass spectrum in1AGeV heavy-ion collisions

1997 ◽  
Vol 56 (6) ◽  
pp. R2920-R2923 ◽  
Author(s):  
R. Holzmann ◽  
M. Appenheimer ◽  
R. Averbeck ◽  
Y. Charbonnier ◽  
H. Delagrange ◽  
...  
Keyword(s):  
Mass Spectrum ◽  
Invariant Mass ◽  
Heavy Ion Collisions ◽  
Invariant Mass Spectrum ◽  
Heavy Ion ◽  
Dilepton Invariant Mass ◽  
Ion Collisions
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